A father who believed his four daughters were conspiring to have him hospitalised and take control of his property left them just 25% of his estate in a will made while suffering from delusions. Michael Gwilliam, from Gloucestershire, England, believed his daughters were plotting against him for financial gain and arranged his inheritance accordingly. When he died in February 2022, aged 79, his daughters discovered that most of his estate had been left to other relatives and people close to him. They challenged the document in court, arguing that their father’s mental condition had affected his ability to make decisions about his inheritance. In January 2026, the High Court ruled that his delusions had influenced the will and declared it invalid, allowing his four daughters to inherit under intestacy rules.
How a father’s relationship with his daughters deteriorated
Michael Gwilliam had previously enjoyed a good relationship with his four daughters and his former wife, Christine. He lived at a farmhouse in the Forest of Dean, Gloucestershire, and had consciously decided against making a will because he wanted his estate to pass to his daughters under the rules of intestacy.However, his behaviour began changing in late 2013. He became increasingly convinced that neighbours were deliberately harassing him, making noises around his property and attempting to force him to sell his farmhouse.His concerns gradually developed into a wider belief that people were conspiring against him. He began spending nights outdoors, watching his property and attempting to identify those he believed were responsible.The situation became serious enough for him to be detained under Section 2 of the Mental Health Act in February 2014 for assessment and treatment. Medical professionals identified persecutory delusions and hallucinations, but Gwilliam did not accept that he was mentally unwell.
Why he believed his daughters were plotting against him
After his hospitalisation, Gwilliam began suspecting that his daughters, particularly Helen, were involved in a conspiracy against him.He believed they had deliberately arranged for him to be detained so they could take control of his finances and property. He also accused them of wanting to obtain power of attorney, sell his farmhouse and take possession of his belongings.His beliefs extended to accusations that his daughters had stolen his possessions and medication. He also thought they were attempting to have him declared incapable of managing his own affairs.The court later found that these beliefs had no factual foundation. His daughters had sought medical intervention because they were concerned about his deteriorating behaviour and wanted him to receive appropriate care.Medical records and evidence from people who knew him showed that his suspicions persisted despite repeated attempts to persuade him that he was mistaken.
The will that left his daughters with just 25% of his estate
On December 3, 2014, Gwilliam signed his only will, changing the inheritance arrangements he had previously intended.Under the document, 75% of his residuary estate was divided equally between his sister, Sheila Gwilliam, his companion Joan Brooks and his nephews. His four daughters were collectively allocated the remaining 25%, meaning each would receive 6.25%.The will also contained a forfeiture provision intended to penalise beneficiaries who challenged its validity.The accompanying letter of wishes contained accusations against his daughters. It claimed they had conspired with their mother to have him detained and wanted to take control of his property and finances.According to the BBC, the estate was valued at between £750,000 and £1 million, making the disputed inheritance particularly significant for the family.
What the High Court discovered about his mental condition
The four daughters challenged the will, arguing that their father lacked the mental capacity required to make it because his decisions were influenced by fixed delusions.The case, Ginger & Others v Mickleburgh & Others, was heard by the High Court following a seven-day trial in August 2025.Judge HHJ Leslie Blohm KC examined extensive evidence, including medical records, police reports, correspondence, diary entries and testimony from family members and healthcare professionals.The court found that Gwilliam was suffering from late-onset schizophrenia associated with an organic disorder of the brain. His condition caused fixed beliefs that his neighbours were harassing him and that his daughters were conspiring to take his property.The judge noted that these beliefs continued even when family members and medical professionals attempted to explain that they were unfounded.The court also considered evidence of his increasingly disturbed behaviour, including spending nights outside his home, brandishing an air rifle and making threats against people he believed were responsible for the harassment.The judge concluded that his beliefs about his daughters were not ordinary suspicions or disagreements within a family. They were delusions that he could not be persuaded to abandon through rational discussion.
Why the court declared the will invalid
The central legal issue was whether Gwilliam possessed testamentary capacity when he signed the document.The court applied the legal principles established in the 1870 case Banks v Goodfellow. Under this test, a person making a will must understand the nature and effect of the document, the extent of their property and the claims of people who might reasonably expect to benefit from their estate.A mental disorder does not automatically invalidate a will. However, a delusion that influences the distribution of an estate can undermine testamentary capacity.In Gwilliam’s case, the judge found that his false belief that his daughters were conspiring against him prevented him from properly considering their claims to his estate.The judgment stated that had he not been suffering from those delusions, he would not have made the will at all. He would have continued with his earlier intention of allowing his daughters to inherit under intestacy rules.The judge therefore ruled that the December 2014 document was void for lack of testamentary capacity.
Why the court also examined the role of his sister and companion
The proceedings also examined whether Gwilliam’s sister Sheila and companion Joan had influenced his views about his daughters.The daughters brought an alternative claim of fraudulent calumny, alleging that the two women had knowingly made false statements about them to turn their father against them and influence his inheritance decisions.The judge found that both women had made statements to Gwilliam that reinforced his suspicions and intended to induce him to make a will that was less favourable to his children.However, the fraudulent calumny claim was unsuccessful. The court was not satisfied that the women knew their statements were false or were reckless about their truth. It found that they genuinely believed the allegations they were making, even though those beliefs were unfounded.The distinction was important because proving fraudulent calumny required more than establishing that false statements had been made or that they had influenced the deceased.
Four daughters set to inherit under intestacy rules
With the 2014 will declared invalid, Gwilliam was legally treated as having died without a valid will.This meant his estate would be distributed under England and Wales’ intestacy rules, under which his four daughters were entitled to inherit as his next of kin.Speaking to the BBC after the ruling, one of the daughters, Ginger, described the outcome as an “unbelievable relief” after a long and difficult legal battle.She said the family felt vindicated and was pleased that their father’s longstanding wishes had finally been upheld.The ruling also established that a person’s apparent ability to discuss and sign a will does not necessarily mean they possess the legal capacity to make one. The court’s decision centred on the effect of Gwilliam’s delusions on his understanding of his daughters’ claims when he decided how his estate should be distributed.