There are, however, complications. In most cases where a conviction is overturned, there is clear (often DNA) evidence to show that the accused person did not commit the crime. In the Bain case, it seems that the evidence still leaves room for doubt - and there is the further complication that, on the facts of this particular case, if he is innocent, there was only one other person who could have done it.
But David Bain does not have to prove his innocence, or that someone else did it, nor is he responsible if his acquittal casts suspicion on someone else.
The real complexity arises, however, because the legal test applied to the question of whether he is entitled to compensation is quite different from the one that determined his guilt or otherwise.
David Bain was acquitted because the test in a criminal case is whether there was a reasonable doubt about his guilt - and the jury found that there was. His claim for compensation, on the other hand, falls under an "extraordinary circumstances discretion" by which the Cabinet will consider "claims on a case-by-case basis, where this is in the interests of justice", and in circumstances where these terms are not defined.
Simon Power, the minister who appointed Justice Binnie to report on this issue, specified that "innocence on the balance of probabilities is a minimum requirement". The onus was on David Bain therefore to establish, on a balance of probabilities, his factual (and not merely technical) innocence as a condition of his receiving compensation.
Justice Binnie's conclusion is that, following a review of all the evidence, David Bain discharged that responsibility and is entitled to compensation.
It is that finding Ms Collins has chosen to question.
The minister is of course faced with a dilemma, and one that arises because public opinion, as far as one can tell, is divided on whether David Bain can be regarded as "innocent" on a balanceof probabilities, and not merely "not guilty".
The minister fears that if she advises the Cabinet that compensation should be paid, a substantial body of opinion will accuse her of unjustifiably paying out taxpayers' money to someone who does not deserve it.
Yet, if she does not do so, what basis can she claim for that decision?
Short of a full and further judicial hearing, which is surely out of the question, does she claim to know better than the courts, and to believe that David Bain is guilty? What does she claim to know that eluded an eminent Canadian jurist engaged to give an authoritative opinion on precisely the issue of David Bain's innocence and that would now lead her to assert that, on a balance of probabilities, he committed the crime?
It is precisely because she can have no sound basis for unilaterally reaching for such a conclusion that she has cast around for someone else to get her off the hook.
But going back to the Solicitor-General, who is surely parti pris, or asking for further opinions until - presumably - she gets one she likes, cannot resolve her dilemma for her.
What, therefore, should she do?
The two possible outcomes both carry with them the risk of serious injustice.
On the one hand, to pay compensation to a David Bain who had killed his family would be to reward a criminal at the taxpayers' expense. But, on the other hand, to deny an innocent David Bain compensation for 13 years in prison for a crime he did not commit would be to add insult to injury, in the dual sense that fairness had been denied to the victim of a terrible wrong, and that he had been left with an ineradicable stigma in the eyes of his fellow citizens - a stigma that our courts felt themselves not justified in imposing.
There is surely no doubt that the latter outcome carries the greater risk of injustice.
Judith Collins should set aside political calculation and concern for what some elements of public opinion may think, and reach the only decision that can minimise potential injustice. She should support her own justice system and the report commissioned by her predecessor, and advise the Cabinet accordingly.
Bryan Gould is a former Labour MP in Britain and a former law don at Oxford University.