3. Let it be presumed that each of A and B is charged, on a joint trial, with the murder of X in circumstances where it is apparent that one or both of them is or are guilty. The defence of each is that the other is solely responsible. The Crown leads forensic and other evidence, some of which tends to establish A's guilt and some of which tends to establish B's guilt. The Crown also leads, but only as against B, evidence of a video-taped confessional statement by B in which he unambiguously admits that, alone and without assistance, he killed X. The Crown alleges, but B disputes, that the confessional statement was voluntarily made. In B's trial, the critical question for the jury is likely to be whether, in the context of the forensic and other evidence supporting A's guilt, B's confessional statement should be accepted as voluntary and reliable. There is obvious force in the argument that it would be unsatisfactory from the point of view of the administration of justice if, in those circumstances, the trial judge was, at the request of the Crown, obliged to direct the jury that, regardless of whether they considered that B's confession of guilt was voluntary and reliable, they were bound to disregard it in the trial of A. The result would be that A's trial was conducted on the arguably illogical and unfair basis that the question whether there was a reasonable doubt about A's guilt had to be resolved by the jury without regard to material which was, if reliable, inconsistent with such guilt and which the Crown itself had placed before the jury (in B's trial) on the basis that, even assessed by reference to the criminal standard of proof, it was, at least in part, reliable.