the view that he did at times suffer from the delusion that Zoran was not his son, although the delusion was likely to have waxed and waned. In her opinion it would have been entirely consistent with Bane’s delusional disorder that at times he should have thought Zoran was his son, and at other times that he was not. Furthermore, with regard to the oral evidence she warned against the danger for a layman of underestimating or downplaying what is said by a person suffering from a delusion in a misguided attempt to impose normality upon that person’s utterances and to interpret them if at all possible in a rational manner. 168. In my judgment Dr Reveley’s warning about the dangers of seeking to impose a rational construction on the utterances of a disordered mind is an important and valuable one, which I have done my best to keep in mind. On balance, however, I am unable to agree with her modified conclusion that there were at least some occasions when Bane really believed Zoran not to be his son. Two reasons in particular lead me to this conclusion. First, it was Professor Howard’s evidence that the content of a delusion, once it has become established, is usually constant. Accordingly, if Bane had really believed Zoran not to be his son, one would expect to find repeated evidence of this delusion from the mid 1980s onwards, particularly given the wealth of documentary material that survives. Dr Reveley agreed with Professor Howard that the content of delusions is usually constant, and although she sought to draw a distinction between constancy over a period of weeks or months on the one hand and over a period of years on the other hand, suggesting that in the longer term delusions may in fact change as other things intrude, I did not find this a convincing explanation for the paucity of the evidence in the present case if Bane did indeed suffer from this particular delusion. 169. My second reason is that, in Professor Howard’s experience, when a person holds delusional ideas about not being the biological parent of his children, such ideas tend to be persistent, vigorously expressed, and to cause enormous distress within the family. As Professor Howard put it in cross-examination: “I think believing that your children are not yours is one of the most fundamentally biologically upsetting things anyone could imagine … I have had experience of families where people have believed that with delusional intensity, and it is the kind of thing that is very difficult to keep suppressed … So I … believe very strongly that had [Bane] had a delusion that his son wasn’t his, he would have expressed that very, very vigorously and angrily and repetitively in his writings, and he doesn’t.” I accept that evidence, and prefer it to Dr Reveley’s more tentatively expressed opinion that delusional ideas about paternity may fluctuate over time. 170. In fairness to Dr Reveley, I should also add that she did not regard this particular supposed delusion as a major peg for her diagnosis, and made it clear that she would have reached the same conclusions about Bane’s testamentary capacity even if she was wrong on this particular point. Nevertheless, the question is an important one, even if only to eliminate it, because if Bane had truly been labouring under the delusion that Zoran was not his son when he made the 1988 and 1989 Wills it is hard to see how he could possibly have had testamentary capacity.