This guide is maintained as a current resource for July 2026 and covers only the laws of England and Wales. Information is for general guidance, not legal advice. Consult a qualified solicitor for advice specific to your situation.
Comprehensive guide explaining when and how a will can be challenged in England and Wales for lack of testamentary capacity, including the legal test from Banks v Goodfellow, evidence, practical steps, common questions and risks.
A will may be contested in England and Wales if the person who made it - the testator - lacked the mental capacity required to understand what they were doing at the time the will was prepared and signed. This issue, known as lack of testamentary capacity, is a recognised legal ground for challenging a will's validity and is one of the most common reasons contested probate disputes arise. This guide explains how capacity is assessed, what evidence is typically needed, the legal test applied by the courts, and what practical steps may be involved in pursuing this type of claim.
What ‘Lack of Capacity' Means in Will Law
Legal capacity in the context of wills is different from general mental capacity defined under the Mental Capacity Act 2005. For wills, the courts apply a common‑law test to determine whether the testator had sufficient testamentary capacity at the time the will was made. This difference exists because the question arises retrospectively - often after the person has died - and focuses specifically on understanding the will‑making act.
The Legal Test: Banks v Goodfellow
The test for testamentary capacity is derived from the nineteenth‑century case Banks v Goodfellow (1870) and continues to be applied by the courts. Under this test, a person must be able to demonstrate the following at the time of making the will:
- Understanding the nature and effects of making a will
The testator must comprehend that they are making a will and that it determines how their property will be distributed after death. - Understanding the extent of their property
The testator must have a general awareness of the property and assets they own - not necessarily detailed financial knowledge, but enough to understand the scope of what they are disposing of. - Appreciating the claims of potential beneficiaries
They must recognise the people who might reasonably expect to benefit, such as close family members or dependants, and consider (even if they choose not to provide for them) how the distribution affects these people. - Freedom from disorders that influence decisions
No disorder of the mind should “poison his affections, pervert his sense of right, or prevent the exercise of his natural faculties”. This means that delusions or impaired judgement should not materially influence the terms of the will.
If a will fails this test, the court can declare it invalid on grounds of lack of capacity. The estate will then be distributed according to an earlier valid will or, if none exists, in accordance with the intestacy rules.
Presumption of Capacity and Shifting Burden of Proof
The law generally starts with a presumption that the testator had capacity, particularly where a will appears rational and was properly executed. This presumption can be challenged if evidence raises a real doubt about capacity. Once doubt is raised, the burden of proof may shift to those defending the will to demonstrate that the testator did, in fact, have capacity.
Evidence Used in Capacity Challenges
Successfully contesting a will on capacity grounds typically requires strong evidence that the testator lacked understanding at the relevant time. Common forms of evidence include:
- Medical records and expert opinions
Records from general practitioners, hospitals, memory clinics, or other healthcare professionals can show cognitive impairment or conditions such as dementia. Medical experts may be asked to provide retrospective capacity assessments. - Witness statements
Testimony from people who knew the testator may describe behaviours, confusion, or unusual conduct around the time of will‑making. - Professional notes
Solicitors' notes from when the will was drafted can be significant, especially if they include observations on the testator's understanding and instructions. - Personal documents
Diaries, emails, or other writings from the testator may indicate cognitive clarity or impairment.
Practical Steps in Challenging for Lack of Capacity
If you believe a will should be challenged on capacity grounds, the following practical steps are commonly involved:
- Review the Will and Context
Identify any irregularities in the document, unusual provisions, or departures from previous wills that could signal a lack of understanding. - Gather Evidence Promptly
Early collection of medical records, witness statements and related documentation strengthens the prospect of establishing a real doubt about capacity. - Seek Legal Advice
Specialist solicitors in contentious probate can help assess the strength of the case and guide evidence gathering, caveats, and litigation steps. - Consider Entering a Caveat
If probate has not yet been granted, a caveat can be entered with the Probate Registry to prevent a grant of probate pending further investigation. - Issue Court Proceedings
If informal resolution is not possible, proceedings may be issued in the civil courts to argue lack of capacity as a ground for invalidity.
Risks and Considerations
Challenging a will on capacity grounds is complex and can be costly, with no guarantee of success. Courts give considerable weight to testamentary freedom, and a rational will - even by someone with some mental impairment - is not necessarily invalid. Evidence must be compelling and relevant to the specific time the will was made.
Common Questions
Can someone with dementia make a valid will?
Yes. A diagnosis of dementia does not automatically mean lack of capacity. The key question is whether the person met the legal criteria at the exact time the will was formulated and signed.
Is lack of capacity the same as lack of understanding legal terms?
No. A testator need not understand complex legal terminology; critical factors are understanding the act of making a will, the nature and extent of their property, and the persons who might expect to benefit.
Does signing in the presence of a solicitor prove capacity?
Professional involvement and recorded capacity assessments can support the presumption of capacity, but they do not guarantee that a will is beyond challenge if sufficient contrary evidence exists.
Key Takeaways
A will can be challenged in England and Wales on the ground that the testator lacked testamentary capacity at the time it was made. The legal standard is drawn from Banks v Goodfellow and requires an understanding of the nature of making a will, the extent of one's estate, and the claims of potential beneficiaries, free from disorders affecting judgement. Contesting a will on these grounds requires substantial evidence and careful procedural steps, and courts generally presume capacity unless a real doubt is raised. Early professional advice and prompt action are essential where lack of capacity is suspected.
