Two poles are identifiable: one is that people who are actually innocent should receive compensation after erroneous conviction, and the other is that no one who is actually guilty should receive compensation after erroneous conviction. By "erroneous" conviction I mean not in accordance with the law.
The problem is to navigate between these poles when interpreting the criteria for compensation. In this case it was the interpretation of s 133 of the Criminal Justice Act 1988[UK] that governed the issue, in particular the phrase "a new or newly discovered fact shows beyond reasonable doubt that there has been a miscarriage of justice". The Court split 5-4 on what this should mean.
The dissenters were particularly revolted by the thought that a person who was in fact guilty might receive compensation after erroneous conviction. Lord Brown (with whom Lord Rodger agreed without delivering a separate judgment) said at :
Lady Hale succinctly addressed Lord Brown's "palpable sense of outrage" :
Under this test there will be occasions where people who are in fact guilty are entitled to compensation. Such cases may occur where, as Lord Brown mentioned at  a person against whom there is inadmissible intercept evidence that unequivocally demonstrates his guilt, could not on admissible evidence be convicted.
The answer to that difficulty is that compensation in such cases should be derisory only. An award of contemptuously small compensation would show society that the person was in fact guilty, and it would deter such people from seeking compensation.
It should be stressed that this case does not establish a meaning for "miscarriage of justice" beyond its specific statutory context. As Lord Phillips observed at , this phrase is capable of having a number of different meanings.
Although there are 284 paragraphs in the case, it is easy to read because the judgments are divided into consistent headings, and the dissenters are left to the end under their own heading. Other topics dealt with are the meaning in this context of the phrase "a new or newly discovered fact" and the relationship between the presumption of innocence and a claim for compensation.
In New Zealand this sort of compensation is governed by Cabinet Guidelines introduced in 1998. Claimants have to be alive at the time of the application, have served all or part of a term of imprisonment, had their convictions quashed on appeal without an order for retrial (or have received a free pardon), and must be able to prove on the balance of probabilities that they are innocent of the crime for which they were convicted. This is a more restrictive entitlement than in the UK. There is, however, a "residual discretion" that allows the Crown to consider claims falling outside the guidelines in "extraordinary circumstances" where it is in the interests of justice to do so. So, where a person is acquitted following a retrial he is outside the guidelines, so he must show "extraordinary circumstances" to demonstrate that it is in the interests of justice to award him compensation. This may well mean that if such a person is able to show to a standard higher than the balance of probabilities that he is in fact innocent, it would be in the interests of justice to award him compensation. The guidelines are not, therefore, unduly concerned with failure to compensate people who are really innocent, and they are arguably over-concerned with avoiding compensating people who are really guilty. Some flexibility in the quanta of awards could be a way of making the scheme more just.
The New Zealand Law Commission had recommended the requirement of proof of innocence and para 127 of its 1998 Report No 49 "Compensating the Wrongly Convicted" received citation in Adams, R (on the application of) v Secretary of State for Justice:  Lord Phillips, [173, 175] Lord Kerr. The Commission proceeded on the basis that actual innocence is the justification for compensation, but the majority of the United Kingdom Supreme Court held that excluding from entitlement people who no longer seemed to be guilty but whose innocence could not be established was a heavy price to pay for ensuring that no guilty person ever gets compensation (Lord Phillips at ).
The NZLC Report starts with a controversial assertion, saying in para 1 "The essence of a free society is the freedom of a law-abiding citizen to act without interference by the state." That begs the very question the state has been unable to answer lawfully. In view of the Report's conclusions, it is a tyrant's assertion, requiring the citizen to prove he is law-abiding. Instead, the essence of a free society is the freedom of all people, whether law-abiding or not, to act without unlawful interference by the state. The rule of law requires the state to prove that interference with the citizen's liberty is justified. The United Kingdom Supreme Court's majority approach survives the moral analysis advocated by Dworkin (see my review of "Justice for Hedgehogs" 25 April 2011), whereas the New Zealand one does not.