It can be difficult to establish that a single will is invalid due to the testator's lack of testamentary capacity.  In the recent case of Clitheroe v Bond  the deceased's daughter had the task of (and succeeded in) establishing that two wills made by her late mother were invalid for just that reason.

Among the various issues, including theft, abuse, estrangement and fraudulent calumny (a poisoning of the mind of the testator by one person against another) the case considered the effect of bereavement grief. This topic was also the subject of discussion in the Key v Key case several years ago in which the elderly testator made a will just a week after the death of his wife of 65 years. That will was subsequently held to be invalid. In Clitheroe, the testator had lost her daughter to cancer and, as in Key, the 'Golden Rule' was not followed.  

In order for a will to be valid "no insane delusion shall influence his [the testator's] will in disposing of his property...which, if the mind had been sound, would not have been made." In Clitheroe it was held that the testator had been suffering from a complex grief disorder (including depression) that affected her mind so as to impair her testamentary capacity. The court was satisfied the testator suffered insane delusions but also that her mind was poisoned by not being able to accept one daughter was going to die and projecting guilt of that onto the other.

It is another reminder to will drafters that a lack of testamentary capacity can take many and multiple forms and is not limited to perhaps more obvious conditions such as dementia. Severe or complex grief, following the death of someone close, can impact upon capacity as can a sudden severe illness or even depression. Practitioners need to be aware of any circumstances which may give rise to a will being challenged and to ensure they keep full notes of their discussions with the testator so that their file is as comprehensive as possible, should they decide to proceed with instructions. Instructions for a will provided by a third party, even family (as happened here), should always be treated with caution.