The High Court has overturned a 2014 will at the centre of a long-running family dispute, in a case which clarifies the law on testamentary capacity and mental illness.
Claire Cox (pictured), partner at Gloucestershire law firm Willans LLP, won the case on behalf of the four daughters of Michael Gwilliam of the Forest of Dean, who died in 2022. The firm successfully challenged a will made by the deceased in 2014, on the basis that Gwilliam had lacked capacity due to late onset schizophrenia.
The court found that Gwilliam’s delusions led him to wrongly believe that his four daughters were stealing from him and tried to have him sectioned for their own financial gain – none of which the court found to be true. Gwilliam had appointed an experienced paralegal to prepare the 2014 will on the advice of his sister, despite previously insisting he wanted to be intestate so his daughters would inherit the whole of his estate.
The 2014 will left the majority of Gwilliam’s estate to his sister, ex-girlfriend and nephews (the defendants in the case), with his four daughters receiving just 25% between them.
Ruling the will invalid and finding that Gwilliam did die intestate, the High Court said it gave “little weight” to the evidence of the will writer, who said she believed Gwilliam had capacity at the time the will was drafted. The decision has wider importance for solicitors, families and professionals involved in supporting older or vulnerable individuals, Cox said, reinforcing the importance of robust safeguards when preparing wills.
She added:
“This was a harrowing case for our clients, but we are pleased that the court recognised the impact of Michael’s serious mental illness on testamentary decision‑making. The judgment reinforces the importance of good practice of solicitors obtaining contemporaneous capacity reports where there are any questions as to testamentary capacity.”
The complex and emotionally charged dispute was ongoing for over four years and involved extensive medical evidence, witness testimony and expert psychiatric opinion, with the written decision published this week running to 99 pages.
Following the outcome, Gwilliam’s daughter said Cox had handled the case with “exceptional skill, clear guidance and steadfast support”.
“She handled difficult opposing solicitors with authority and professionalism, and her dedication to our case was invaluable. Claire and the supporting team at Willans got us justice for our father, finally.”
Helen Ginger & Ors v Robert Mickleburgh & Ors [2026] EWHC 100 (Ch)
Read Claire Cox’s case summary in Today’s Wills and Probate on Thursday.
