This guide is maintained as a current resource for September 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.
Understand testamentary capacity in England and Wales. Learn the legal test, how courts assess capacity, and how to avoid disputes when making or challenging a will.
Testamentary capacity is a fundamental legal requirement for making a valid will in England and Wales. It refers to a person's mental ability to understand and approve the contents of their will at the time it is created. If a person lacks testamentary capacity, the will may be declared invalid, potentially leading to disputes, court proceedings, and the estate being distributed under intestacy rules.
This guide explains testamentary capacity in clear terms, including the legal test, how it is assessed, the risks of challenges, and the practical steps individuals can take when planning their estate.
What Is Testamentary Capacity?
Testamentary capacity is the legal standard used to determine whether a person is capable of making a valid will. It focuses on the individual's mental state at the time the will is executed.
A person must be able to:
- Understand that they are making a will
- Understand the nature and extent of their estate
- Understand who might reasonably expect to benefit
- Make decisions free from mental disorder or delusion that affects the distribution
If these requirements are not met, the will can be challenged and potentially set aside by the courts.
The Legal Test for Testamentary Capacity
The leading authority on testamentary capacity is the case of Banks v Goodfellow. This case established the legal principles that are still applied today.
Under this test, a person must:
- Understand the nature of making a will and its effects
- Understand the extent of the property they are disposing of
- Be able to comprehend and appreciate the claims to which they ought to give effect
- Not be affected by any disorder of the mind that influences the distribution of their estate
This remains the primary legal framework used by courts when assessing whether a will is valid.
Relationship with the Mental Capacity Act 2005
Testamentary capacity is distinct from general mental capacity under the Mental Capacity Act 2005, although the two concepts are closely related.
The Mental Capacity Act provides a broader framework for decision-making capacity, including:
- Presumption of capacity unless proven otherwise
- The requirement to support individuals in making decisions
- The principle that capacity is decision-specific and time-specific
In practice, courts may consider both the Banks v Goodfellow test and the statutory principles when assessing whether a person had capacity to make a will.
When Is Testamentary Capacity Assessed?
Capacity is assessed at the time the will is made and executed.
This means:
- A person may lack capacity at one point but have it at another
- A will made during a “lucid interval” may still be valid
- Later deterioration in mental health does not invalidate a will made when capacity existed
This time-specific approach is critical in disputes involving conditions such as dementia.
Common Situations Where Capacity Is Questioned
Testamentary capacity is often challenged in circumstances involving:
Dementia or Cognitive Decline
Conditions such as Alzheimer's disease may affect a person's understanding and decision-making ability.
Serious Illness
Terminal illness or medication can impair mental clarity.
Mental Health Conditions
Disorders that affect reasoning or perception may raise concerns.
Significant Changes to a Will
Unexpected or substantial changes to beneficiaries may prompt scrutiny.
Vulnerability to Undue Influence
Where a person is dependent on others, there may be concerns about pressure or manipulation.
These situations frequently lead to disputes and court proceedings.
How Courts Assess Testamentary Capacity
When a will is challenged, the courts in England and Wales examine evidence to determine whether the legal test has been satisfied.
Medical Evidence
Medical records, GP notes, and expert opinions are often crucial.
Witness Evidence
Statements from solicitors, family members, and witnesses to the will may be considered.
The “Golden Rule”
In cases involving elderly or seriously ill individuals, it is considered best practice for a medical professional to assess capacity at the time the will is made. This is commonly referred to as the “Golden Rule”.
Although not legally binding, failure to follow this practice may increase the risk of a successful challenge.
Legal Process for Challenging a Will
If testamentary capacity is disputed, the matter may be resolved through negotiation or formal court proceedings.
Grounds for Challenge
A will can be challenged on the basis that:
- The testator lacked testamentary capacity
- The will was executed improperly
- There was undue influence or fraud
Court Proceedings
Disputes are typically handled in the High Court (Chancery Division), which deals with probate and inheritance matters.
Burden of Proof
Initially, the person propounding the will must show it was properly executed. If there is real doubt about capacity, the burden may shift to prove that the testator had the required mental ability.
Time Limits for Claims
Different time limits may apply depending on the nature of the claim:
- Challenges to the validity of a will (including lack of capacity) do not have a strict statutory time limit, but delays can affect the case
- Claims under the Inheritance (Provision for Family and Dependants) Act 1975 must usually be brought within 6 months of the grant of probate
Early action is important to protect legal rights and prevent estate distribution before a dispute is resolved.
Risks of Failing to Address Testamentary Capacity
Failing to properly consider testamentary capacity can result in serious legal consequences:
Invalid Wills
A will may be declared invalid, leading to intestacy rules applying.
Legal Disputes
Challenges can result in lengthy and costly court proceedings.
Delays in Probate
Disputes over capacity can significantly delay estate administration.
Financial Loss
Legal costs and potential redistribution of assets can reduce the estate's value.
Emotional Impact
Disputes often involve close family members and can be highly distressing.
Practical Steps to Reduce Risk
When starting or updating estate planning, the following steps can help reduce the risk of disputes:
Seek Professional Advice
Solicitors experienced in wills and probate can ensure legal requirements are met.
Document Capacity Clearly
Keep detailed records of discussions and decisions.
Obtain Medical Assessment Where Appropriate
Particularly important for elderly or vulnerable individuals.
Follow Proper Execution Procedures
Ensure the will is signed and witnessed correctly.
Review the Will Regularly
Changes in health or circumstances should prompt a review.
Taking these steps can strengthen the validity of a will and reduce the likelihood of successful challenges.
Common Questions About Testamentary Capacity
Can someone with dementia make a valid will?
Yes, if they meet the legal test at the time the will is made. Capacity is assessed at that specific moment.
What is a “lucid interval”?
A period during which a person with impaired capacity temporarily regains sufficient understanding to make valid decisions.
Who decides if a person had capacity?
If disputed, the courts determine this based on evidence.
Does a doctor need to confirm capacity?
Not always, but medical evidence is highly advisable in higher-risk situations.
Why Testamentary Capacity Matters
Testamentary capacity is a central requirement in estate planning in England and Wales. Without it, a will may be invalid, leading to intestacy, disputes, and significant legal costs.
The principles established in Banks v Goodfellow remain the foundation of the law, supported by modern frameworks such as the Mental Capacity Act 2005. Understanding and properly addressing capacity-particularly in cases involving age, illness, or vulnerability-is essential for ensuring that a will is legally valid and reflects the testator's true intentions.
Careful planning, proper documentation, and professional guidance can significantly reduce risks and provide certainty for both the individual and their beneficiaries.
