Kahneman’s Thinking, Fast and Slow

Everyone is reading Daniel Kahneman's "Thinking, Fast and Slow" (2011). A passage in a recent New Zealand Court of Appeal decision, the details of which are currently suppressed, raises questions about the right way to think about propensity evidence.

The case citation is [2011] NZCA 645 and the date of the decision is 14 December 2011. I will call it X v R. I will also adapt the quotation from para [34] of the judgment to comply with the order suppressing identifying particulars of the appellant:

"... it is an unlikely coincidence that Mr X, twice within a year, would be the hapless and innocent victim of being apprehended driving a car with [other people in it and also with evidence of criminal offending in it]. The evidence goes directly and cogently to the key issue: did Mr X know of the [items] found in the car he was driving on [the second occasion]?"

While the conclusion that the evidence had sufficient probative value to be admissible is intuitively correct, this form of reasoning entails several thinking errors of the kind that Kahneman discusses.

There is a tendency to draw strong conclusions from incomplete information (the "what-you-see-is-all-there-is" error). We are not told anything about the frequencies that matter in the above case: how frequently do people who are guilty of the present sort of offending have a previous recent incident of this sort of police apprehension, compared with how frequently do people who are innocent of offending of the present kind have a recent previous such apprehension?

There is a substitution error: we tend to answer difficult questions by answering a much simpler related question. Here it is easy to answer the question about the recent apprehension and to apply that answer to the more difficult question of guilt on the present occasion. This is closely related to another error.

Base-rate neglect is the error of neglecting statistical likelihoods in favour of accepting what could be causally possible. The other evidence in the case, relating directly to guilt on the present occasion, may significantly affect the strength of our tendency to see a causal connection between the first apprehension and the second.

Another error is the halo effect, or in the present context what might be called the devil's horns effect. Having learnt something bad about the defendant's behaviour on an earlier occasion, we are tempted to overemphasise this when we consider his present guilt.

Further, there is the narrative fallacy: we are tempted to accept what we can build into a story that makes sense, although the events may in reality be unconnected. The defendant may have been innocent on the earlier occasion through lack of knowledge of the presence of the things in the car. The coincidence may be real, but it does not suit the story we are tempted to build in which we cast the defendant as a recidivist.

This is similar to another error, the representativeness bias. Where only partial information is available we lean heavily on stereotypes.

For a review of Kahneman's book summarising these and other thinking errors, see the article in the New Zealand Listener, January 21-27, 2012, by David Hall.

In the above case, where the issue was the defendant's knowledge of the presence of the things in the car, it is easy to build a narrative in which the defendant, being ignorant on both occasions, was simply associating with people who were both his friends and offenders. That too would be a combination of thinking errors.

Courts too often make assumptions about likelihoods without inquiring into occurrences in the real world. The correct approach is Bayesian, as Kahneman – a leading psychologist and Nobel laureate – recognises. But that requires the effort of careful analytical thought rather than our preferred instinctive assessment of circumstances.

Admissibility of eyewitness identification evidence

Just as I was sneaking back to the Southern Hemisphere the Supreme Court of the United States delivered its decision in Perry v New Hampshire. I have previously noted the submissions that the Court received in this case on the vulnerability of eyewitness identification to error.

The reasoning is necessarily tied to the constitutional jurisprudence on due process, so I just summarise the effect of the decision in terms that may be of more general interest.

Sotomayor J dissented, but the majority held, in a decision delivered by Ginsberg J, that there is no need for a trial judge to have the power to exclude such evidence on grounds other than unfairness to the defence. Irregularities in the conduct of an identification can be the subject of trial remedies, such as confrontation and cross-examination, judicial caution to the jury about the need for care before accepting this evidence, and the judicial discretion to exclude the evidence if its illegitimately prejudicial effect outweighs its probative value.

That is a conservative approach. In our neck of the woods we have radically reformed the law: s 45 of the Evidence Act 2006 imposes a burden of proof of reliability on the prosecution where specified formal procedures have not, without good reason, been followed. The standard of proof here is beyond reasonable doubt. The defence may still challenge the admissibility of the evidence if formal procedures have been followed, but the burden is on the defence to prove on the balance of probabilities that the evidence is unreliable. These provisions are discussed in R v Edmonds [2009] NZCA 303 at [79]-[128] (sorry keen readers, not currently available online). The issue for the judge is whether the evidence is sufficiently reliable to go to the jury, not whether the evidence establishes identity to the relevant standard. Proof of reliability is distinguished from proof of identity, and the focus for the prosecution's burden is on the circumstances in which the identification was made. It does not include other evidence suggesting guilt, such as a confession.

There are issues concerning the interpretation of s 45 that remain to be explored. Its application in judge-alone trials has been considered by the Supreme Court: Harney v Police.

Extended secondary liability: assessing the risk

"Where 2 or more persons form a common intention to prosecute any unlawful purpose, and to assist each other therein, each of them is a party to every offence committed by any one of them in the prosecution of the common purpose if the commission of that offence was known to be a probable consequence of the prosecution of the common purpose."

So says s 66(2) of the Crimes Act 1961 [NZ], defining extended secondary participation in offending. The contentious phrase has been "a probable consequence", giving rise to arguments about whether a common intention to use one form of violence, for example, made the use of another more serious form a probable consequence. In turn this led to arguments that use of a knife was not a probable consequence of the use of, say, a common intention to use a baseball bat, or that use of a gun was not a probable consequence of, say, a common intention to use of a knife.

In Edmonds v R [2011] NZSC 159 (20 December 2011) the Supreme Court rejected continued development of this line of case law and directed a return to the words of the statute. 

Of course the same issues will continue to arise: was the common intention one which had the probable consequence of the commission of the offence in question? In violent offences the sort of weapon actually used will usually be relevant, but in a way that is directed to the probability of its being used as assessed from the point of view of the defendant who had the original purpose in common with the principal offender.

"[47] The  approach  of  New  Zealand  courts  to  common  purpose  liability  must  be firmly  based  on  the  wording  of  s  66(2).   That  section  recognises  only  one  relevant level of risk, which is the probability of the offence in issue being committed.  If the level  of risk  recognised  by  the  secondary  party  is  at  that  standard,  it  cannot  matter that the actual level of risk was greater than was recognised.  It follows that there can be  no  stand alone  legal  requirement  that  common  purpose  liability  depends  on  the party’s knowledge that one or more members of  his or her  group were  armed or, if so, with what weapons.  As well, given the wording of s 66(2), there is no scope for a liability  test  which  rests  on  concepts  of  fundamental  difference  associated  with  the level  of  danger recognised  by  the  party.    All  that  is  necessary  is  that  the  level  of appreciated risk meets the s 66(2) standard."

From this it is clear, or at least so it seems to me, that (i) the risk recognised by the secondary party is the risk he actually perceived, not the risk he ought to have perceived, (ii) if the secondary party perceives the risk as a "probable consequence" that is sufficient for his liability, (iii) the secondary party may recognise that risk without knowing that the principal party has a weapon, (iv) there are no gradations of the culpable risk - either the preceived risk is of a "probable consequence" or it isn't.

It follows that evidence of the alleged secondary party's knowledge of the possession of a weapon of a different kind from that actually used is relevant not as itself a criterion for liability but rather as material to whether those criteria are met.

This approach to extended secondary liability will apply by analogy to all offences, not just those involving violence. The central issue is whether the alleged secondary party had what amounted to a belief that commission of the actual offence was a probable consequence of the common intention to commit the originally intended offence. It will not be necessary to prove that the alleged secondary party knew that the principal had the means to commit the actual offence, but if he did know that the means existed that would be relevant to assessing whether he had the necessary perception of probable consequence.

As the Court points out (49), it is for the prosecutor to say what the alleged common intention was. The closer the commonly intended offence was to the commission of the offence that was actually committed, the easier it should be to prove that the latter was a probable consequence of commission of the former.

This decision puts extended secondary liability back on the statutory track, away from which the case law had allowed it to drift. However the role of the phrase "in the prosecution of the common purpose" in s 66(2) could still give rise to debate. In committing the offence for which extended secondary liability is contended, did the principal offender go outside - and bring to an end - the prosecution of the common purpose? Had commission of the commonly intended offence been abandoned? This sort of issue is not likely to arise in cases of violence, where the use of force can be seen as a continuum with the commonly intended offence merging with the one for which extended liability is in question. While Edmonds deals with an aspect of extended secondary liability, other problems in applying s 66(2) will need to be addressed.

Fair trials without central witnesses

It is possible for a trial to be fair without a central witness giving evidence in person and being cross-examined. The witness's evidence may be read at trial but the fact-finder may still have adequate means of testing the reliability of that evidence.

A fair trial is one where the law is accurately applied to facts that are determined impartially. Impartiality can exist when an unbiased fact-finder uses adequate means to assess the reliability and weight of the evidence.

It might be that there are corroborative witnesses who do give evidence and who can be cross-examined. There might also be a similarity between the evidence of independent complainants that is so unlikely to be coincidence that their mutual reliability is virtually assured. In such cases, where the defence can cross-examine the witnesses who support the absent witness, there may be found to be sufficient factors to counter-balance the absence of the central witness so that the defendant is not deprived of a fair trial.

But in other cases the absence of the central witness may not be counter-balanced. There may be no corroborative oral testimony. There may be no evidence that the defence could call to contradict the absent witness. In such cases the fact-finder may be unable to impartially assess the reliability of the absent witness, there being no one for the defence to cross-examine on the central issues.

The rule against hearsay, the exceptions to that rule, and the rule excluding evidence when its probative value is outweighed by the risk of improper prejudice to the defence, are the means by which the common law has endeavoured to ensure the fairness of trials when witnesses are not available for cross-examination. Often these rules have become statutory.

Over the last few years a storm gathered in Europe over this. The European Court of Human Rights had developed a rule that a conviction could not be based on the evidence of a witness who could not be cross-examined if the evidence of that witness was central to the prosecution case in the sense of being the sole evidence against the defendant or of being decisive evidence against him: Unterpertinger v Austria judgment, 24 November 1986, § 33, Series A no. 110. The UK Supreme Court criticised this rule in R v Horncastle [2009] UKSC 14 (noted here as an update to the entry on Al-Khawaja and Tahery v R [2009] ECHR 110, 27 January 2009), and only the most obtuse reader would fail to see that if the Grand Chamber did not allow the UK courts to continue to apply the discretionary approach rather than the Strasbourg rule, continued participation of the UK in European criminal law would be unlikely.

So inevitably Strasbourg yielded and departed from its rule. On appeal from the Chamber decision in Al-Khawaja and Tahery, the Grand Chamber held 15-2 that the rule did not apply where the law of a State contained sufficient safeguards: [2011] ECHR 2127 (15 December 2011).

The majority held that the underlying principle is that the defendant in a criminal trial should have an effective opportunity to challenge the evidence against him (127). The question was whether there were sufficient safeguards to secure the defendant's right to a fair trial (130).

"[142] ...  the defendant must not be placed in the position where he is effectively deprived of a real chance of defending himself by being unable to challenge the case against him. Trial proceedings must ensure that a defendant’s Article 6 rights are not unacceptably restricted and that he or she remains able to participate effectively in the proceedings. ... The Court’s assessment of whether a criminal trial has been fair cannot depend solely on whether the evidence against the accused appears prima facie to be reliable, if there are no means of challenging that evidence once it is admitted."

The phrase "not unacceptably restricted" is a bit alarming at first blush, suggesting perhaps that sometimes a restriction on the right to a fair trial will be acceptable. But this is not what was meant. The article 6 rights include subsidiary rights to the right to a fair trial, and restrictions on those have always been tolerated when necessary as long as they do not compromise the defendant's absolute right to a fair trial.

So, where there are restrictions, there must be adequate safeguards (145):

"Also, in cases concerning the withholding of evidence from the defence in order to protect police sources, the Court has left it to the domestic courts to decide whether the rights of the defence should cede to the public interest and has confined itself to verifying whether the procedures followed by the judicial authorities sufficiently counterbalance the limitations on the defence with appropriate safeguards. The fact that certain evidence was not made available to the defence was not considered automatically to lead to a violation of Article 6 § 1 (see, for example,Rowe and Davis v. the United Kingdom [GC], no. 28901/95, ECHR 2000 II). Similarly, in the case of Salduz, cited above, § 50, the Court reiterated that the right to legal assistance, set out in Article 6 § 3 (c) was one element, amongst others, of the concept of a fair trial in criminal proceedings contained in Article 6 § 1."

These safeguards must "counterbalance" the limitations on the defence (147):

"... The question in each case is whether there are sufficient counterbalancing factors in place, including measures that permit a fair and proper assessment of the reliability of that evidence to take place. This would permit a conviction to be based on such evidence only if it is sufficiently reliable given its importance in the case."

So when the majority speak of balancing the interests of the defence, the victim, witnesses and the public interest (146) as an approach to the overall fairness of the proceedings, that is a compendious way of referring to a two-stage assessment: first the balancing of competing interests in relation to subsidiary rights, and second the assessment of the effect of that balancing on the defendant's right to a fair trial.

The partly dissenting judgment of Sajo and Karakas JJ views the majority's counterbalancing approach as uncertain and inadequate protection of a defendant's rights, diminishing the value of human rights in Europe. That may be a little exaggerated, as there can be no doubt that the majority would agree with Sajo and Karakas JJ's dictum:

"While we understand the nature of the challenges faced by the prosecution when key witnesses die or refuse to appear at trial out of genuine fear, the protections guaranteed by Article 6 speak only to the rights of the defence, not to the plight of witnesses or the prosecution. The task of this Court is to protect the accused precisely when the Government limit rights under the Convention in order to bolster the State’s own position at trial. Counterbalancing procedures may, when strictly necessary, allow the Government flexibility in satisfying the demands of Article 6 § 3 (d). Our evolving application of the sole or decisive test, however, shows that this exception to the general requirement of confrontation is not itself without limits in principle. In the end, it is the job of the Government to support their case with non-hearsay corroborating evidence. Failure to do so leaves the Government open to serious questions about the adequacy of their procedures and violates the State’s obligations under Article 6 § 1 in conjunction with Article 6 § 3 (d)."

And their concluding quotation was from a New Zealand case, R v Hughes [1986] 2 NZLR 129 (CA) at 148-149:

"We would be on a slippery slope as a society if on a supposed balancing of the interests of the State against those of the individual accused the Courts were by judicial rule to allow limitations on the defence in raising matters properly relevant to an issue in the trial. Today the claim is that the name of the witness need not be given: tomorrow, and by the same logic, it will be that the risk of physical identification of the witness must be eliminated in the interests of justice in the detection and prosecution of crime, either by allowing the witness to testify with anonymity, for example from behind a screen, in which case his demeanour could not be observed, or by removing the accused from the Court, or both. The right to confront an adverse witness is basic to any civilised notion of a fair trial. That must include the right for the defence to ascertain the true identity of an accuser where questions of credibility are in issue."

Although statute has permitted the limitation of the right of a defendant to know the identity of a witness in certain limited circumstances, the right to a fair trial remains absolute in New Zealand, as no doubt it does in the United Kingdom.

Beyond the bounds of legal pragmatism

When an orthodox application of the criteria for criminal responsibility does not meet the requirements of public policy, the law must change. When it is left to judges to make the change, existing institutions or concepts are likely to be adapted to meet social requirements.

In R v Gnango [2011] UKSC 59 (14 December 2011) Lord Kerr dissented in his orthodox application of the principles of party liability. He held that neither primary liability as principal offender nor secondary liability either as an aider, abettor, counsellor or procurer, or by reason of extended secondary liability (the sort of common enterprise-gone-wrong that in this case all judges agreed to call parasitic accessory liability) applied to the facts.

The facts were simple and are found in the statement of the question of law that arose in this case:

"If (1) D1 and D2 voluntarily engage in fighting each other, each intending to kill or cause grievous bodily harm to the other and each foreseeing that the other has the reciprocal intention, and if (2) D1 mistakenly kills V in the course of the fight, in what circumstances, if any, is D2 guilty of the offence of murdering V?"

It was a gunfight. There was no room for extended secondary liability here because any agreement that D2 may have had with D1 could not sensibly include agreement that D1 should shoot at him.

So D2 could only be guilty if he was a principal or if he aided, abetted, counselled or procured D1 in the killing of V who was an innocent by-stander. It should be obvious that he was not a principal, as he did not actually commit the murder himself. This was not obvious to Lords Brown and Clarke, and neither but to a lesser extent to Lords Phillips, Judge and Wilson. But they were engaged in extending the law for policy reasons.

The difficulty with orthodox secondary liability was that in this case the jury had not been invited to consider whether there was an agreement that D2 would be shot at, so even if this absurd possibility were a potential basis for liability it was not relevant to this appeal.

D2 could not have aided (etc) D1 in the killing of V unless he had helped (etc) by agreeing to be shot at.

Lord Kerr was correct in orthodox terms to conclude that there was no basis in the circumstances of this appeal to hold D2 liable for the murder of V.

That conclusion was not good enough for the other judges.

Lord Phillips and Lord Judge, with Lord Wilson agreeing, took the extremely pragmatic approach of saying it doesn't matter whether D2 was a principal or a secondary party, he and D1 both acted dangerously in a public place and each should be held accountable for V's death. Either could have killed someone and it was just fortuitous that the person who fired the fatal shot was D1. These judges, and Lord Dyson, preferred the secondary liability route to responsibility but they agreed with Lords Brown and Clarke that principal liability could also be used as the basis for liability.

Nor does the jury have to agree on the basis for liability: it is the conclusion as to guilt that requires agreement, not the route to that conclusion (63).

Well, you can't just pluck someone out of an unruly mob and say this person could easliy have been the one who caused the relevant harm so he should be held responsible for it even if it is known that he didn't actually do it himself. Nor can you pretend that he intentionally assisted or encouraged the commission of an offence when there is no evidence he meant to help or encourage its commission. Yes, the law must further the interests of the community, but there must be a rational, formalist, basis for attributing responsibility for crime. Otherwise we will have a society in which judges can simply say we shouldn't let this person off so we will hold him liable.

The strength of vagueness

Two vague but fundamental concepts

The first vague concept: abuse of process

Complicity by Australian officials in the unlawful deportation of the defendant (appellant) to Australia led to subsequent criminal proceedings against the defendant in Australia being stayed as an abuse of process in Moti v R [2011] HCA 50 (7 December 2011).

Abuse of process is open-ended, not to be confined to rigid categories of official misconduct (60):

" ... the forms of expression adopted in the decided cases must be understood in the context of the particular facts of each case. None should be read as attempting to chart the boundaries of abuse of process. None should be read as attempting to define exhaustively the circumstances of removal of an accused to this country that warrant exercise of the power to stay criminal proceedings against that person or as giving some exhaustive dictionary of words by one or more of which executive action must be described before proceedings should be stayed. None should be read as confining attention to whether any act of an Australian Government official constituted participation in criminal wrongdoing, whether as an aider and abettor or as someone knowingly concerned in the wrongdoing. And the use of words like "connivance", "collusion" and "participation" should not be permitted to confine attention in that way. All should be understood as proceeding from recognition of the basic proposition that the end of criminal prosecution does not justify the adoption of any and every means for securing the presence of the accused. And in this case, as in others, the focus of attention must fall upon what Australian officials did or did not do."

Recognition of abuse of process is a response to the policy of even-handed justice and the maintenance of public confidence in judicial process.

"57. ... two fundamental policy considerations affect abuse of process in criminal proceedings. First, "the public interest in the administration of justice requires that the court protect its ability to function as a court of law by ensuring that its processes are used fairly by State and citizen alike" [Williams v Spautz [1992] HCA 34; (1992) 174 CLR 509 at 520]. Second, "unless the court protects its ability so to function in that way, its failure will lead to an erosion of public confidence by reason of concern that the court's processes may lend themselves to oppression and injustice" [[1992] HCA 34; (1992) 174 CLR 509 at 520]. Public confidence in this context refers to the trust reposed constitutionally in the courts to protect the integrity and fairness of their processes. The concept of abuse of process extends to a use of the courts' processes in a way that is inconsistent with those fundamental requirements."

Here the official misconduct was in summary (63):

"...First, Australian officials (both in Honiara and in Canberra) knew that the senior representative of Australia in Honiara at the time (the Acting High Commissioner) was of opinion that the appellant's deportation was not lawful. Second, the Acting High Commissioner's opinion was obviously right. Third, despite the expression of this opinion, and its obviously being right, Australian officials facilitated the unlawful deportation of the appellant by supplying a travel document relating to him (and travel documents for those who would accompany him) at a time when it was known that the documents would be used to effect the unlawful deportation. That is, Australian officials supplied the relevant documents in time to be used, with knowledge that they would be used, to deport the appellant before the time for deporting him had arrived."

The majority, French CJ, Gummow, Hayne, Crennan, Kiefel and Bell JJ, held that proceedings on the indictment should be permanently stayed.

Heydon J delivered an interesting dissent, focused on difficulties arising from the vague concepts concerning abuse of process and its lack of definition. Among the points he makes is the availability of alternative, disciplinary, responses to official misconduct instead of giving a person who may be guilty of serious offending immunity from conviction.

There are also some observations in this case on payment of prosecution witnesses, which was another ground of this appeal but which did not need to be considered in detail as no impropriety in that regard was held, unanimously, to have occurred.

The second vague concept: miscarriage of justice

In Handlen v R; Paddison v R [2011] HCA 51 (8 December 2011) the High Court held that the proviso could not be applied where a trial had proceeded on a mistaken appreciation of how participation in the offending could be proved. The requirements for secondary liability, namely that each appellant had intentionally aided, abetted, incited, counselled or procured the commission of the offence, should have been applied. (An alternative form of secondary liability was not relevant in this case.) But the trial proceeded wrongly on the basis that proof of membership of a joint criminal enterprise would be sufficient if commission of the relevant offence was part of that enterprise. The error is that not every member of such an enterprise is necessarily a party to every offence committed by members of the enterprise. This was overlooked by all counsel and by the trial judge. The Court of Appeal of the Supreme Court of Queensland had recognised the error but had applied the proviso because it was satisfied that the appellants were guilty, and there had not been a departure from the fundamental requirement of a trial according to law.

"47. As this Court explained in Weiss v The Queen, there is no single universally applicable description of what constitutes a "substantial miscarriage of justice" [[2005] HCA 81; (2005) 224 CLR 300 at 317]. The appellants were convicted of serious criminal offences ... following a trial at which the prosecution case was conducted, and left to the jury, on a basis for which the law did not provide. The conduct of the trial on this basis conferred an evidentiary advantage on the prosecution, leading to the admission of evidence to prove the existence and scope of the group exercise. Ultimately, the issue posed for the jury was whether the prosecution had proved that the appellants were parties to the group exercise when this was irrelevant to proof of their complicity in Reed's offences. The verdicts on the importation counts reflect the jury's satisfaction that each appellant was a party to the group exercise but it does not follow that the jury must have been satisfied of the facts necessary to establish the appellants' guilt of the importation offences in the only way for which the law allowed. It was not open to the Court of Appeal to apply the proviso in the circumstances of these appeals."

The majority ordered a new trial, Heydon J dissented and would have dismissed the appeals. He analysed the evidence and found guilt proved regardless of how the trial had been conducted. He did not see the defects as fundamental. For the majority, regardless of the strength of the evidence the trial had been such a departure from what was in accordance with the law that, in effect, the right to a fair trial was the dominant consideration.


Vague concepts can still be useful in the law. Reasonableness, fairness, interests of justice, the public interest, the weighing of values underlying rights, do not need to be defined as if they were mathematical concepts. Numbers too, when used in measurements, involve margins of error and require probabilistic reasoning. These areas of vagueness are opportunities for the exercise of judgment. Complaints about vagueness are like the formalists' complaints about pragmatism.

An unruly heckler at the back of the room might cry out that Heydon J had, in the first of these appeals, been too much the formalist, while in the second he had been too much the pragmatist.

Equality before the law, parity of sentence

Some general points on disparity of sentence can be gleaned from Green v R; Quinn v R [2011] HCA 49 (6 December 2011). The case needs to be read in its statutory context which includes a constraint on prosecution appeals against sentence. But aside from that,

• An appeal by an offender on the basis that his sentence was excessive by comparison to that imposed on a co-offender may be allowed to avoid disparity, even if the result is an inadequate sentence, as long as the result is not an affront to the administration of justice (French CJ, Crennan and Kiefel JJ at 33).
• A prosecution appeal against sentences imposed on some co-offenders should not give rise to a disparity with more lenient but un-appealed sentences imposed on other co-offenders (French CJ, Crennan and Kiefel JJ at 37).
• An appeal court should not introduce procedural unfairness by basing its judgment on a perceived defect in the decision of the court below when on the hearing of the appeal the defect was not mentioned and was not the subject of argument (French CJ, Crennan and Kiefel JJ at 76, 80).
• Intermediate courts of appeal should only overrule their own decisions infrequently and in exceptional circumstances, when the earlier decisions are manifestly wrong and not based on principle worked out in clear lines of useful authority (Heydon J dissenting in the result).
• Parity must not be conflated with proportionality, because the starting point is the appropriate sentence for the particular offence. Different offending may justify different sentences which should not be criticised as being disparate (Bell J dissenting, Heydon J agreeing, at 125).
  Prosecution appeals may not be allowed if the result would be disruption to rehabilitation, as the benefit of guidance to other courts may come at too high a cost in terms of justice to the individual (French CJ, Crennan and Kiefel JJ at 43).

Obviousness and obfuscation

Civil proof of offending

It should be obvious that proving something to the civil standard does not undermine failure to prove it to the criminal standard.

Blindingly obvious though this may be, it has troubled the Strasbourg judges. The UKSC was briefly troubled by it (R v Briggs-Price, noted here 2 May 2009), but more recently it was not: Gale v Serious Organised Crime Agency [2011] UKSC 49 (26 October 2011).

Again in Gale the context was civil proceedings for the recovery of property to a value equivalent to the proceeds of serious criminal offending. The judge had applied the civil standard of proof to the issue of the commission of such offences. The Supreme Court unanimously upheld that approach.

There was some delicate treatment of Briggs-Price, and what was the minority view there was now unanimously approved: 47-54. This was achieved by admirably obscure reasoning, perhaps inspired the confusing nature of the Strasbourg jurisprudence.

The presumption of innocence, and the finality of acquittals, are not compromised where in civil proceedings for the recovery of the proceeds of crime the court is satisfied on the balance of probabilities that criminal offending had occurred.



Waiver of the right to legal advice

Another thing that you would have thought was obvious is that a person can waive the right to legal advice without having to receive legal advice about waiver and its consequences.

This point had to be decided in McGowan (Procurator Fiscal, Edinburgh) v B (Scotland) [2011] UKSC 54 (23 November 2011).

Difficulties concerning the effectiveness of waiver can arise from the different rights that may be waived and from whether the alleged waiver was express or implied. But in all cases, waiver must be shown to have been "voluntary, informed and unequivocal" (Lord Hope at 17). "Informed" waiver will not exist if there is reason to believe the defendant had not understood the right that was being waived (36, 38, 44), but a defendant can understand without legal advice (46). The court will, however, proceed cautiously where the defendant is of low intelligence or is vulnerable for other reasons (47).

Further (49), if a defendant declines legal advice, the police should mention that such advice can be obtained by telephone, and if the defendant still declines, the police should ask why and record the answer. That, at least, would be best practice although not an absolute rule (50) [and see also Jude v HM Advocate (Scotland) [2011] UKSC 46 (23 November 2011)]. It could also be wise to advise the defendant that legal advice could be given without cost to him (51).

There was a time when courts took a more tight-sphinctered approach to what was adequate advice of the right to consult a lawyer. In R v Piper [1995] 3 NZLR 540 (CA) for example, it was thought to be unnecessary to inform the defendant that the consultation would occur without the police overhearing it. But now we have the Chief Justice's practice direction (issued under s 30 of the Evidence Act 2006) which requires privacy to be mentioned. It also requires mention of the availability of free advice.

Another point I should make about waiver is this. Waiver is a more sensible requirement to use than is consent. The issue should not be whether the defendant "consented" to police questioning, but rather whether he waived his right to legal advice and to silence. Similarly, in the context of searches, the issue should not be whether the defendant "consented" to a search, but whether he waived his right not to be searched. As anyone can see, it is incongruous to think that a defendant in possession of incriminating material would freely consent to being searched by the police, but less so to think that he might waive his right not to be searched.

Conviction appeals – burdens and risks

How sensitive should an appellate court be to the risk that an error at trial was sufficient to require the quashing of a conviction and the ordering of a retrial?

The proviso has been the traditional legislative criterion, and its formulation has usually used the concept of a substantial miscarriage of justice. That is, an error at trial would not require the quashing of a conviction if it was not a substantial miscarriage of justice.

There was therefore a distinction between miscarriages of justice that were not substantial, and those that were. The former could be termed harmless errors, and the latter errors that may have affected the result of the trial.

But what does "may have affected" mean for this latter group?

In R v Sarrazin 2011 SCC 54 the majority declined to draw distinctions between various grades of risk of affect on the outcome. At [27] Binnie J said:

"It seems to me that there is a significant difference between an error of law that can be confidently dismissed as "harmless", and an assessment that while the error is prejudicial, it is not (in the after-the-fact view of the appellate court), so prejudicial as to have affected the outcome. Such delicate assessments are foreign to the purpose of the curative proviso which is to avoid a retrial that would be superfluous and unnecessary but to set high the Crown's burden of establishing those prerequisites. The same can be said for the other branch of the curative proviso. As a result, the burden of the Crown to demonstrate an "overwhelming" case or a "harmless" error of law should not be relaxed."

What is interesting about this for those of us who are about to come under a reformed legislative regime is this. The burden has shifted from the Crown to the appellant on the issue of whether an error at trial was harmless. Formerly the Crown had to satisfy the appellate court that the error was harmless, now the appellant will have to satisfy the appellate court that it was not.

Only one submission to the select committee on the criminal procedure bill mentioned this point.

Section 232 of our Criminal Procedure Act 2011 materially avoids any distinction between substantial miscarriages of justice and those which are not substantial. The appeal court must allow an appeal if it is satisfied that a miscarriage of justice had occurred, and that means that there is a real risk that the outcome of the trial was affected by the error. There are other aspects, but these are the ones directly in point here.

How will an appellate court interpret "real risk"? Is there to be a gradation of risks, of the sort that the Supreme Court of Canada majority found unacceptable? Or is a real risk anything more than a harmless error or one which occurred in any case other than one where the prosecution's case was overwhelming?

As the dissent of Deschamps, Rothstein and Cromwell JJ in Sarrazin illustrates, opinions can differ over whether there was a reasonable possibility that an error could have affected the verdict.

In the circumstances of that appeal, the majority's approach, which was that failure by the judge to put to the jury the alternative of an attempt amounted to a substantial miscarriage of justice, is preferable to the minority's speculation on how the jury was thinking. Under the New Zealand reformed law, the majority's reasoning would lead to a conclusion that the trial had been unfair because it was not according to law. That is an alternative ground for finding a miscarriage of justice under s 232.

When our hair was black

In the course of considering the alleged naivety of Jonathan Sumption (UKSC blog 9 November 2011) I reached for my copy of "Equality" by Joseph and Sumption, which when it was hot off the press I reviewed for the University of Auckland students' newspaper in 1979.

Those were the days when Sumption's hair was black, as indeed was mine. Here is mine:

His was more flamboyant:

The book is an argument against taxation-imposed redistribution of wealth. The UK was then in the grip of rampant taxation of the rich. The authors' style has a formidable clarity that is only available to the very brilliant.

But although I now forget what I said about the book at the time (update: here is a copy of my review), it seems to me that insistence on logical rigor on matters of social policy has the same weakness I mentioned here on 3 November 2011. Relatively immature cognition favours logic over the weighing of values that should underlie policy reasoning.

Sumption has delayed taking his position on the UKSC bench so that he can work on an important case. He will receive a spectacular fee for that. In 1979 he and Joseph said (p 69):

"In practice, people will not work beyond the point at which the burden of the extra work exceeds the pleasure of the extra money."

Given that the work of a lawyer is generally not particularly burdensome, one can see how the balance may fall.

But people do work for reasons other than "the pleasure of the extra money." There are some burdensome areas of criminal law practice, as anyone who defends the children of the poor will realise. Legal aid returns can be insignificant compared to the burden of the work.

There is naivety in Joseph and Sumption's book. It seeks to shield its glib assumptions behind an insistence that only logic can rebut its argument. Dworkin's hedgehog has the better view. Compare the starkly different views of what is the business of the State. Joseph and Sumption (67):

"It is no business of the State to decide in advance what kind of society it ought to be governing and then to manipulate or frustrate known desires in such a way as to bring such a society into being. It must take its subjects as it finds them. It is means, not ends, which are the proper concerns of governments. It is their proper function to provide a framework of laws and institutions within which men can pursue ambitions of their own devising, and thereby create whatever society is the natural outcome of the infinite variety of human tastes and personalities."

Dworkin (352-354):

"Coercive government is legitimate only when it attempts to show equal concern for the fates of all those it governs and full respect for their personal responsibility for their own lives.

"... [E]verything the government of a large political community does – or does not do – affects the resources that each of its citizens has and the success he achieves. ... [T]he impact of ... personal variables on his actual resources and opportunities must in every case also depend on the political variables: on the laws and policies of the communities in which he lives or works.

"... [W]e cannot avoid the challenge of equal concern by arguing that the resources an individual has depend on his choices, not the government's choices. They depend on both."

Dworkin's conception of the purpose of government is more nuanced and more realistic.

Just to be even-handed, I should confess that around the same time as Joseph and Sumption were writing their short book I was writing an essay for a Masters tutorial on the hallmark requirement for the admissibility of similar fact evidence, in which I asserted that absence of a hallmark can itself be a hallmark. Even now my toes curl and I blush. True it may be that in some contexts the offender who has no hallmark may thereby be distinguished from other suspects, but more generally absence of a hallmark has no probative value. How young I was, how innocent. But the difference is that whereas my error was a simple slip of logic, easily corrected, Sumption's is a neglect of pragmatism. Experience tells us that weak judges tend to rely on logic at the expense of pragmatism. "The life of the law has not been logic, it has been experience."

Informer privilege

Both the state and a police informer may have an interest in keeping confidential the identity of the informer. But such confidentiality is subject to a defendant's right to a fair trial. A defendant may make his own inquiries into the identity of an informer, but this must be done with care to avoid conduct that obstructs the course of justice.

The line may be crossed, for example, if the defendant tries to obstruct prosecution proceedings by suggesting that he will disclose an informer's identity. In R v Barros
2011 SCC 51 (26 October 2011) that was alleged.

It is in the public interest that false claims of informer privilege are disallowed. The person may have been a participant in the offending to an extent that protection of confidentiality is not warranted. He may have instigated the offending. Both the defendant, and when the case gets to trial, the judge, have an interest in ensuring that claims to confidentiality and privilege are properly based.

Where there is a proper basis for informer privilege it is granted - without the balancing of competing interests that may be undertaken in other areas such as confidentiality relating to journalists' sources – but only if the defendant's right to a fair trial would not be compromised [33-35].

The Canadian approach seems consistent with that in New Zealand: Evidence Act 2006, ss 53, 64, 67.

NZSCBlog

[Update: the "NZSC blog" seems to have disappeared. I imagine that students are under too much pressure to produce quality beyond the limitations that their inexperience inevitably imposes. Not to worry, it was an ambitious plan.]

Congrats to the University of Auckland Law School on starting the New Zealand Supreme Court Blog. I enjoyed the analysis of Elias CJ's discussion of what academics call the third source of governmental power in Hamed v R.

I wonder if judges anonymously create their own blog sites and comment on each other's judgments. Perhaps they could adopt noms de keyboard and post rebuttals of critical assessments of their work.

I don't allow comments because my early experience was that they are just irritating, whether from judges or not.

Anyway, the new blog is off to a promising start, so I have added a link to it. This does not mean that I agree with its criticism of the CJ's judgment. It is possible that law schools still place emphasis on technical legal reasoning - identification of the ratio of a decision, recognition of precedents, distinguishing or applying other cases - which is formalist, at the expense of policy reasoning which is essentially pragmatic. The Supreme Court is a policy court. It is not bound by decisions of other courts, and is probably not even bound by its own decisions. It is concerned with finding the best solution to legal problems in the light of the judicially-perceived policy that best serves the current needs of our society. If it gets that wrong, the legislature can intervene.

Posner, in "How Judges Think" at 220-221 is particularly good on this topic, as are generally his chapters 7 and 8.

So, what sort of society do we want to live in? One where the police can approach people at random and ask if they may search their bags? People who think that the executive can do anything that is not specifically proscribed would have to accept that sort of society. Or do we prefer a society in which the police can only put questions to people when they have lawful authority to do so? I think our desire for freedom from executive interference supports this alternative. As it happened, the CJ did not support her conclusion with policy reasoning other than in a broad sense by reference to the significance of the Bill of Rights. Her formalist approach to what was essentially a question of pragmatism might reflect the schoolroom (but I prefer to doubt that), and has drawn formalist criticism. Both her approach and the criticism have mis-fired here.

I should add, while I am in this mood to be helpful, that a prime illustration of formalism being developed to an academic extreme and then discarded in favour of pragmatism is Field v R, discussed here on 27 October 2011.

What’s the word for ...?

Procedural fairness aims at facilitating substantive fairness. Sometimes procedural rights are so close to the right to a fair trial that there is no room to argue that notwithstanding breach of procedural fairness there was a fair trial. An argument along these lines was rejected in Abdula v R [2011] NZSC 130 (1 November 2011).

The Supreme Court in this case laid down procedural guidelines for the use of interpreters in trials in the future [60]. Those procedures had not been followed in this case. At [44] the Court said:

"The consequence of a breach of the right to the assistance of an interpreter under s 24(g) [of the New Zealand Bill of Rights Act 1990] is a breach of the right to a fair trial under s 25(a). We do not accept as correct the Crown's submission that, once a breach of the right to assistance of an interpreter is shown, the court must exercise a judgment as to whether the accused nevertheless had a fair trial. Rather, a properly established breach – the failure to meet the required standard – necessarily makes the trial unfair. In those circumstances, it is axiomatic that a substantial miscarriage of justice will have occurred. There can accordingly be no resort to the proviso under s 385(1) of the Crimes Act 1961.[Footnote: R v Condon [2006] NZSC 62, [2007] 1 NZLR 300 at [77]]"

In my view, this question of "failure to reach the required standard" marks the boundary between procedural unfairness and substantive unfairness. While the Court seems to be denying any distinction between the right to assistance of an interpreter and the right to a fair trial, it can only remove the distinction by employing the "required standard" concept. Really, the standard required of interpreters is that of avoiding trial unfairness.

Another interesting feature of this case is that the appellant has succeeded in establishing a rigorous procedure for future cases but not his own. The question for the Court then became, notwithstanding the departures in this case from the new standard was there any defect that resulted in an unfair trial here? The Court does here exactly what the Crown had "unsuccessfully" submitted it should do at [44] quoted above. But it does that by using the "required standard" analysis.

Failure of the appellant here was not surprising, because his counsel could not demonstrate any instance where failure of accurate interpretation impeded the conduct of the defence at trial [59]. Of course it would be difficult for counsel to do that here, as the words used by the interpreter were not known. On the facts, however, the defendant had at trial expressed no concern over the adequacy of the interpretation – but then, how could he know what was adequate?

In appeals like this (rape) there might be a public perception that the Court would do everything it could to avoid a retrial. Fortunately for the public perception of the administration of justice there seems to be sufficiently careful scrutiny of the circumstances in this judgment to put such concerns to rest.

Voices of reason

Thanks are due to UKSCBlog for drawing our attention to video interviews with some of the Justices, published by the Guardian.

We simply don’t do that

Acceptance of a bribe can occur after the performance of an act beneficial to the payer and without any expectation of payment when the act was done: Field v R [2011] NZSC 129 (27 October 2011).

This is because [59] "it is simply wrong for an official to accept money or like benefits in return for what has been done in an official capacity."

And [61] an environment would otherwise be created where

"(a) an official who receives such benefits will come to expect similar benefits in the future and is likely to act accordingly; and

(b) members of the public who know about, or suspect, what has happened will come to believe that unless they too provide such benefits, they will not receive dispassionate consideration and, if prepared to provide such benefits, will receive corresponding advantages."

Any expressions to the contrary as might be detected in previous cases or law commission reports didn't matter.

"[62] ... there is a fundamental inconsistency between the performance of official functions and the acceptance of private rewards for doing so. In large measure this is a corollary of the first reason in the paragraph above. But associated with this are related expectations about the way in which those in official positions, including Members of Parliament, can be expected to act. This consideration is also illustrated by the facts of the present case."

But there is room for courtesies:

"[65] ... if there is an exception, it must address the extent of the gift and the particular context in which it occurs. We consider, therefore, that there must be a de minimis defence in relation to gifts of token value which are just part of the usual courtesies of life."

As to the element that a bribe be accepted "corruptly",

"[66] ... In part it captures the requirement for a defendant to have acted knowingly. In the present case, this requirement required the Crown to establish that the appellant knew that the services he received were provided in connection with the immigration assistance he gave, meaning that he knowingly engaged in conduct which the legislature regards as corrupt. As well, it is the presence in s 103(1) (and like provisions) of the word "corruptly" which permits the de minimis exception to liability which we accept exists."

Deflecting the jury from its fundamental task

"The instructions which a trial judge gives to a jury must not, whether by way of legal direction or judicial comment on the facts, deflect the jury from its fundamental task of deciding whether the prosecution has proved the elements of the charged offence beyond reasonable doubt."

Hargraves v The Queen; Stoten v The Queen [2011] HCA 44 (26 October 2011) at [45] per French CJ, Gummow, Hayne, Crennan, Kiefel and Bell JJ.

It was a potential breach of this for the judge to direct the jury that in assessing the defendant's evidence they could take into account his interest in the verdict.

Other examples of possible deflection of the jury from their task mentioned here are comment on the defendant's failure to give evidence [43] and asking the defendant in cross-examination why the complainant is lying [44].

Deflection of the jury from its fundamental task is a miscarriage of justice. Whether deflection has occurred in a particular case must be assessed in the context of the whole of the summing up and the circumstances of the case. As it turned out here, there was no miscarriage, because the jury would not have understood the judge to be saying that the evidence of a defendant must be scrutinised more carefully than that of other witnesses.

Omission? What omission?

For discussion of liability for omissions under the law of the Commonwealth of Australia, see Commonwealth Director of Public Prosecutions v Poniatowska [2011] HCA 43 (26 October 2011).

The majority held that legislation had failed to specify what act that was omitted was necessary for the actus reus of an offence of engaging in conduct that resulted in the obtaining a financial advantage that the defendant knew or believed he was not eligible to receive. Here, conduct is defined as including an omission to perform an act, and an omission is only a physical element of an offence if the law creating the offence makes it so.

The legislature, anticipating this glitch, introduced a new section (s 66A) into the relevant legislation. This enabled the requiring of a person to do a specific act in the relevant circumstances, namely to give information. Omission to do that specified act would apparently be sufficient for this element of the actus reus.

Heydon J, dissenting, criticised the increasing vagueness of statutory criminal law. He referred to

" ... the proposition advanced by the responsible Minister, when the Code was introduced into the House of Representatives in 1995, that it would reflect Benthamite ideals of certainty in the criminal law [footnote: Australia, House of Representatives, Parliamentary Debates (Hansard), 1 March 1995 at 1331]. One does not often encounter a more striking illustration of the vanity of human wishes. That is because very many parts of the Code, including the parts debated in this appeal, are inconsistent with those ideals. They represent a significant regression from the condition of Commonwealth, State and Territory criminal law as it was before 1995. That criminal litigation under the Code is conducted with any semblance of ordered justice is a tribute to the Australian legal profession, not to the Commonwealth legislature."

So, legislatures, sharpen your Act(s). Ho ho.

Some errors of law in judicial fact finding

For a reminder of the kinds of things that can be errors of law arising out of a trial judge's treatment of the evidence, see R v J.M.H. 2011 SCC 45. The headnote summarises them from the judgment of the Court delivered by Cromwell J at [24] – [32]:

"The Crown's right of appeal from an acquittal of an indictable offence is limited to 'any ground of appeal that involves a question of law alone'. The jurisprudence currently recognizes at least four types of cases in which alleged mishandling of the evidence may constitute an error of law alone giving rise to a Crown appeal of an acquittal; this may not be an exhaustive list. First, it is an error of law to make a finding of fact for which there is no evidence. However, a conclusion that the trier of fact has a reasonable doubt is not a finding of fact for the purposes of this rule. Second, the legal effect of findings of fact or of undisputed facts may raise a question of law. Third, an assessment of the evidence based on a wrong legal principle is an error of law. Fourth, the trial judge's failure to consider all of the evidence in relation to the ultimate issue of guilt or innocence is an error of law, but this error will be found to have been committed only if the reasons demonstrate that this was not done. The trial judge's reasonable doubt did not have to be based on the evidence; it could arise from the absence of evidence or a simple failure of the evidence to persuade him to the requisite level of beyond reasonable doubt. It is only where that reasonable doubt is tainted by a legal error that appellate intervention in an acquittal is permitted."

That decision (maple) tree again

If evidence was wrongfully obtained, what is the relevance to its admissibility that it could have been obtained lawfully?

Sometimes failure to use lawful means would aggravate the wrongfulness. Other times the lawful alternative would diminish the wrongfulness. When?

The Supreme Court of Canada got to grips with this in R v Côté 2011 SCC 46 (14 October 2011). The context for this sort of decision in Canada is R v Grant 2009 SCC 32, which I had some fun with here on 18 July 2009 for its complex model of how admissibility of improperly obtained evidence is to be decided. Grant was referred to recently by the Supreme Court of New Zealand in Hamed v R, discussed here on 19 September 2011.

So to the vital bit of Côté. The term "discoverability" means the ability to discover the evidence lawfully. Two "branches" of the Grant model have to be addressed: the seriousness of the misconduct, and its impact on the defendant Cromwell J delivering the joint judgment):

"[71] I turn to the first branch of the Grant test which is concerned with the seriousness of the Charter-infringing state conduct. If the police officers could have conducted the search legally but failed to turn their minds to obtaining a warrant or proceeded under the view that they could not have demonstrated to a judicial officer that they had reasonable and probable grounds, the seriousness of the state conduct is heightened. As in Buhay, a casual attitude towards, or a deliberate flouting of, Charter rights will generally aggravate the seriousness of the Charter-infringing state conduct. On the other hand, the facts that the police exhibited good faith and/or had a legitimate reason for not seeking prior judicial authorization of the search will likely lessen the seriousness of the Charter-infringing state conduct.

"[72] We come now to the effect of discoverability on the second branch of the Grant test — the impact on the Charter-protected interests of the accused. Section 8 of the Charter protects an individual's reasonable expectation of privacy. That reasonable expectation of privacy must take account of the fact that searches may occur when a judicial officer is satisfied that there are reasonable and probable grounds and authorizes the search before it is carried out. If the search could not have occurred legally, it is considerably more intrusive of the individual's reasonable expectation of privacy. On the other hand, the fact that the police could have demonstrated to a judicial officer that they had reasonable and probable grounds to believe that an offence had been committed and that there was evidence to be found at the place of the search will tend to lessen the impact of the illegal search on the accused's privacy and dignity interests protected by the Charter."

Nothing controversial there.

I still think the Canadian model in Grant is absurdly complex: who can visualise a 3-branch balancing exercise? The third branch is the public interest in admission of the evidence. It would be better to think of the first two as being one "branch", or arm of the balance, with a weight moving one way or the other along it according to the first two considerations.

In Grant the model was called a "decision tree". Draw it for us. I had a go, but couldn't say it would make comparison of cases easy.

Previous acquittals as propensity evidence

In Fenemor v R [2011] NZSC 127, the Supreme Court declined to establish a rule excluding, as propensity evidence, evidence of facts on which the defendant had previously been acquitted ("acquittal evidence"). The Court held that in each case admissibility of acquittal evidence will depend on its qualifying under s 40(1) of the Evidence Act 2006 as propensity evidence and then on its surviving the weighing of probative value against risk of unfair prejudice required by s 43.

The Court declined to give examples of when unfairness might make such evidence inadmissible, beyond that mentioned in Degnan [2000] NZCA 321, [2001] 1 NZLR 280 (CA) of an alibi having been the basis for the earlier acquittal. It was preferable that the case law should develop over time as questions of unfairness are very case-specific.

A challenge addressed to the acquittal dimension of the propensity evidence must demonstrate a logical connection between the acquittal and the claimed unfairness.In Fenemor it was argued unsuccessfully that the defendant would have to give evidence if the evidence was ruled admissible and that this was unfair. The Court, upholding the reasoning of the Court of Appeal, held that he would be in the same position if the evidence had led to a conviction, or if no earlier charge had been brought, so there was no logical connection between the acquittal and the claimed unfairness. Similar reasoning applied to a submission that the prior acquittal evidence would lead the jury to reason wrongly. Nor was it correct to argue that it would be unfair to adduce the similar facts that the previous jury had rejected, because that jury had only seen "one frame of what was now known to be a bigger picture" [22].

Assessment of the probative value of the evidence in relation to the present charge is different from assessing its value as proof of the earlier charge, and a priori there is no basis for a general conclusion that acquittal evidence has different probative value from propensity evidence that has not led to any charge [23].

Fruit of the poisoned tree

When may evidence obtained 'downstream' from improperly obtained evidence be admissible? By downstream I mean that the finding of the challenged evidence occurred as a consequence of the improper obtaining of the other evidence.

For example, if the defendant, under improper questioning, gives information to the police about a witness who could vouch for him, and the police consequently question that witness and obtain evidence incriminating the defendant, how should the court decide whether the incriminating evidence is admissible? Facts like this were considered in HM Advocate v P (Scotland) [2011] UKSC 44 (6 October 2011). This is a companion case to that considered in my note yesterday.

The position in domestic Scots law is that if the evidence could be led without reference to the improperly obtained evidence it would not be treated as inadmissible by reason of it having been found as a consequence of the improperly obtained evidence: Lord Hope at 17, citing Lawrie v Muir 1950 JC 19. Similarly, in England and Wales under s 76(4) and 78(1) of PACE 1978 all the circumstances must be considered and the consequential evidence is not invariably excluded: at 18.

As far as Strasbourg jurisprudence went, there was no definitive decision but guidance could be obtained from Gäfgen v Germany (2011) 52 ECHR 1 (noted here on 3 July 2008, Chamber, and Grand Chamber on 25 June 2010): Lord Hope at 22. No rule of automatic exclusion of such consequential evidence has been established 23.

The Supreme Court found some assistance from Canada: Thomson Newspapers Ltd v Canada (Director of Investigation and Research) [1990] 1 SCR 425, where the distinction was made between evidence created by impropriety, and evidence that may have gone undetected but for the impropriety but which nevertheless existed independently.

This was consistent with the conclusion Lord Brown reached 27:

" ... there is no absolute rule that the fruits of questioning of an accused without access to a lawyer must always be held to be a violation of his rights under article 6(1) and 6(3)(c) of the Convention. It is one thing if the impugned evidence was created by answers given in reply to such impermissible questioning. The leading of such evidence will be a breach of the accused's Convention rights unless there are compelling reasons to restrict the right of access: Cadder [v HM Advocate [2010] UKSC 43], para 55. It is another thing if the evidence existed independently of those answers, so that those answers do not have to be relied upon to show how it bears upon the question whether the accused is guilty of the offence with which he has been charged. So far as the accused's Convention rights are concerned, there is no rule that declares that evidence of that kind must always be held to be inadmissible. The question whether it should be admitted has to be tested, as in domestic law, by considering whether the accused's right to a fair trial would be violated by the leading of the evidence."

Lords Dyson, Kerr and Matthew Clarke agreed with Lord Hope, as did Lord Brown in a separate judgment. Lord Brown drew attention to how the admissibility balancing decision would be made in England and Wales under s 78(1) of PACE.

See also the attenuation approach in R v Wittwer (discussed here 6 June 2008), and occasions where a consequential link may be dispensed with but evidence nevertheless excluded: R v Ogertschnig (discussed here 26 October 2008). Improprieties may taint evidence without there being a consequential link, and as the present case shows, improprieties may be irrelevant notwithstanding such a link.