'It's stretching the truth to say there's a strong clinical reason to separate them. Separation would be on psychological grounds, so as part of our investigation there have been lots of psychological tests. It's most important that they understand the risks. I'm trying very hard to make sure they comprehend.

'Each of the twins is prepared to die to give the other one the chance to live. If the separation proceeds, the surgeons have to deal with the possibility of a major catastrophe on their hands. Most doctors prefer to play safe - we're averse to risk. I feel the same way, but I also feel that doing nothing is not best for the twins.'