"It needs to be emphasised and emphasised again that it is the plain duty of a judge summing up a criminal case to a jury to put fairly and sufficiently the defence case. Where a defendant has not given evidence, and in addition has not called any evidence on his behalf, there is no evidence from the witness box in support of that defence other than such evidence as has been gleaned by one way or another from other witnesses which have been called. Where that defendant who has not given evidence has been interviewed in detail and has given an account in interview which is relevant to their defence and which so far as it goes contains their defence, that is evidential material in the way that we have described and it is the duty of the judge, in our judgment, in putting the defence case properly and fairly to make such proper and structured reference in summary to the material in the interview which constitutes the defence case in the criminal trial. That we conceive to be a principle which applies to the present case and in our judgment the judge failed to live up to it. We also accept and emphasise that it will only be in an exceptional case that, such a failure in the summing-up having taken place, this court will conclude that nevertheless the conviction of a defendant subjected to that kind of a summing-up should be regarded as safe. The task of this court is of course to identify whether trials have been properly conducted and whether in particular they have been conducted fully and fairly and whether the judge's summing-up has been a proper, full and fair one. But the statutory function of this court considering an appeal against conviction is to consider whether, nevertheless, if we reach that conclusion as we do in this case, the conviction is safe. If nevertheless we conclude that the conviction is safe, then the appeal will fail, notwithstanding the failure of the judge such as we have indicated."