It is possible to challenge a will on a number of grounds - including that the testator did not have capacity to make the will, or that they were subject to undue influence, or that they did not know and approve of the contents of the will. Often in will challenges, more than one of these will be argued.
This was the case in Hawes v Burgess  EWCA Civ 94. Mrs Daphne Burgess made a will in 1996 dividing her estate between her three children, Julia, Libby and Peter. The family was a close one and Mrs Burgess wished to treat them equally.
In 2006, Mrs Burgess told Julia that she wished to amend her will to include directions for her burial. Julia made an appointment for her to meet with an experienced local solicitor, and attended the meetings with her. The solicitor took the view that Mrs Burgess was 'entirely compos mentis' although she was suffering from dementia of modest severity at the time. In January 2007, Mrs Burgess executed her new will which cut Peter out, apparently because she was planning to make provision for him during her lifetime. In fact, no provision was made for him. Neither Mrs Burgess or Julia mentioned the new will to Peter and Mrs Burgess remained close to Peter until his death in 2009.
Julia attempted to admit the 2007 will to probate. Libby and Peter challenged this on the grounds that it was made at a time when Mrs Burgess lacked capacity and that she did not know and approve of the contents. Julia had the job of proving that this was not the case and that the will was valid.
The judge agreed with Libby and Peter that the will was not valid. Firstly, she found (with the help of expert medical evidence) that whilst Mrs Burgess could understand that she was making a will and the nature of her estate, she was unable to comprehend the claims to which she should give effect - in other words, she had excluded Peter on erroneous grounds (there was no plan to make lifetime provision for him and none was made) and this was due to the vascular dementia that she was suffering.
Secondly, following consideration of all the evidence the judge agreed that Mrs Burgess did not know and approve of the contents of the 2007 will.
Julia appealed to the Court of Appeal on both points.
The Court of Appeal took a slightly different approach. They were conscious of the fact that Mrs Burgess had taken advice from an experienced solicitor who felt that she had capacity. Although he was not medically qualified, he had met her on two occasions. The medical evidence which had been submitted was from an expert who had never met Mrs Burgess.
On the question of capacity, the Court of Appeal was loathe to overturn a will which had been drafted by an experienced independent lawyer and made that clear in the judgments. However, that led to the slightly unsatisfactory position that no decision was made on this point at all.
The Court of Appeal dismissed the appeal instead on the ground that Mrs Burgess had not known and approved of the contents of the will. There was a question about whether the will reflected Mrs Burgess's intentions, and Julia had not satisfied the court that it did. The reasons were that Julia was the one who had made arrangements for Mrs Burgess to see the solicitor; she had remained in the room throughout; she had not made Libby and Peter aware of the change in the will; she had provided inaccurate information to the solicitor (including that Mrs Burgess was planning to make lifetime provision for Peter) and she had done all this at a time when there was a rift between her and Peter which she thought would never be repaired. The judge had said that Julia was the 'controlling force' in making the will, and the Court of Appeal clearly felt that this was correct.
The 2007 will was held to be invalid. By the time of the decision, it was largely irrelevant anyway because the costs were probably more than the value of the estate (which was only worth in the region of £200,000). In addition, the family which had previously been very tight knit, had been damaged probably beyond repair.