The test of mental capacity for making a will includes the 4th limb that "no insane delusion shall influence his will...". Lesley King offers a typically helpful comment on the case of Ramsay v. Ramsay in a Law Society Private Client Section commentary. As Lesley says "One must not set the bar too high", capacity does not have to be perfect. The two passages from Banks v Goodfelow quoted are valuable.
Points for practitioners 1. Courts do not require capacity to be perfect. In 2007, Mrs Ramsay scored 12 out of 28 in a mini-mental state test and the judge accepted that she was suffering from moderate to severe dementia. This did not necessarily mean that she lacked capacity.....the first three elements of the test ‘do not have to be possessed in the highest degree, or even in as great a degree as the testator may formerly have done’.The second deals with memory. While ‘a man in whom the faculty is totally extinguished can not be said to possess understanding to any degree whatever … memory may be very imperfect; it may be greatly impaired by age or disease … and yet his understanding may be sufficiently sound for many of the ordinary transactions of life …’