"... in our judgment it is a course that should only rarely be followed. The problem with the course is that it means that the jury will see a witness apparently giving evidence in one frame of mind and then will come back to that witness after events have occurred in their absence which may have brought about a complete turn about in the evidence that he gives. For such a jury to assess fairly what reliance they can place upon the evidence of a witness will be nigh-on impossible. Therefore, although there may be exceptional circumstances, we do not see that these were such circumstances in this case ..."
"You will have to decide, bluntly, whether you can accept any part of his evidence that he gave to you in court. If you decide that there is a serious conflict between the evidence he gave you and the statements previously by him then you may think that you should reject his evidence all together and not rely upon anything he said as a witness."
"So, members of the jury, effectively he was contrasting what he had said in the police statement in evidence and you may think that during the course of his evidence that there was very little in the statement that he was prepared to adopt. It is a matter for you whether you can accept any part of his evidence at all."