Proof and prejudice

To what extent can trial fairness be sacrificed to the need to establish the truth? The answer depends on whether the case is criminal or civil.

In civil cases, if the parties will not reach a settlement, the court must reach a result. This may mean proceeding to decision notwithstanding some unfairness. In such a case, if unfairness cannot be avoided, at least the court will try to minimise it, and to balance it so that while the trial may not be equally fair to each side, it could be (albeit rather cynically) called equally unfair to each side. The dominating concern in civil cases is to establish the truth insofar as that can be done in compliance with the rules of evidence.

Judges do not, naturally enough, spell this out as plainly as I have just done. Recently, Lord Bingham has referred to truth and fairness, in relation to civil trials, in O’Brien v Chief Constable of South Wales Police [2005] UKHL 26 (28 April 2005), at para 6:

"…In deciding whether evidence in a given case should be admitted the judge's overriding purpose will be to promote the ends of justice. But the judge must always bear in mind that justice requires not only that the right answer be given but also that it be achieved by a trial process which is fair to all parties."

This does not tell us whether impossibility of fairness to all parties prevents the right answer being found. Be that as it may, we are concerned here with criminal cases, and in criminal law, as it is applied in the common law jurisdictions, courts endeavour to balance competing interests.

The criminal law has multiple functions, and they include meeting official misconduct by the exclusion of improperly obtained evidence. In extreme cases a stay of proceedings may be ordered on grounds of public policy. Those grounds are not directly connected to the fairness of the trial. Another ground for excluding relevant evidence is that its probative value is exceeded by its illegitimately prejudicial effect. This latter ground is particularly problematic.

Its application may result in evidence that is highly probative being admitted notwithstanding the significant risk it brings of illegitimate prejudice. See, for a statement of the law, Lord Phillips in para 32 of O’Brien. Sections 101 to 106 of the Criminal Justice Act 2003[UK] now govern this discretion in the United Kingdom.

In criminal cases, the accused’s right to a fair trial is absolute, primary, and essential. This means that reasonable risks of illegitimate prejudice must be avoided. The probative value/prejudicial effect balancing decision needs to be "re-understood" in the light of developments in human rights law.

This crucial development in the law of criminal evidence is something I have written on elsewhere, and readers with robust stamina may wish to see: Mathias, "The Duty to Prevent an Abuse of Process by Staying Criminal Proceedings" in Robertson (ed) Essays on Criminal Law: A Tribute to Professor Gerald Orchard (Brookers, 2004), and Mathias, "Probative value, illegitimate prejudice and the accused’s right to a fair trial" (2005) 29 Crim LJ 8.