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Author and Publication
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Citation
Sharp v Adam [2006] EWCA Civ 449.
Copywright
Copyright © 2026 Nellie Supports Ltd. All rights reserved.
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What is testamentary capacity?
This guide explains what testamentary capacity is, the legal standard a person must meet to make a valid will, and when a formal assessment is worthwhile. It is written for families, executors, solicitors and professionals. It sets out the test in plain terms, the evidence behind a sound opinion, and the situations in which capacity is most likely to be questioned. It does not replace tailored legal advice.
What testamentary capacity means
Testamentary capacity is the legal ability to make a valid will. A person has it if they understand what making a will involves and its effect, have a broad understanding of what they own, can appreciate the claims of those who might expect to benefit, and are not affected by a disorder of the mind that distorts their decision. It is judged at the time the will is made.
The legal test that applies
The standard comes from Banks v Goodfellow (1870), which remains the governing test in England and Wales. It is a common law test and is not the same as the functional test in the Mental Capacity Act 2005. A will is valid or invalid by reference to the four Banks v Goodfellow requirements, not by a generic capacity assessment.
Capacity is specific to the will in question
Testamentary capacity is decision-specific and time-specific. A simple will leaving everything to one person requires less understanding than a complex will dividing a large estate with conditions and trusts. The level of understanding expected rises with the size and complexity of the estate and the choices being made.
How it differs from financial capacity
Testamentary capacity is often confused with capacity to manage property and affairs, but they are separate decisions with different tests. A person may lack the capacity to run their day to day finances yet still have capacity to make a straightforward will, and the reverse can also be true. Each must be assessed on its own terms.
When capacity is most likely to be questioned
Concerns commonly arise where the testator was elderly or unwell, where the will was changed late in life, where it benefits an unexpected person, or where someone close to the testator was involved in arranging it. Cognitive decline, delirium, depression and delusional beliefs can all affect the decision and should be examined rather than assumed.
The role of the assessor
A capacity assessor gathers the relevant evidence, considers each limb of the test against the facts, and forms a reasoned opinion. They should record what they observed directly, separate it from information supplied by others, and explain how any diagnosed condition does or does not affect the will. The opinion should be capable of withstanding challenge.
Why contemporaneous assessment matters
An assessment carried out at or close to the time the will is made is far more valuable than one reconstructed later. It captures the testator's actual understanding and reasoning while it can still be observed. Where a will is high-risk or likely to be contested, a contemporaneous assessment significantly reduces the chance of a successful challenge.
What a sound opinion includes
A sound opinion records the instruction, the date and the will concerned, the Banks v Goodfellow test, the evidence relied on, the findings, an analysis against each limb, and a clear conclusion with any limitations stated. Where the assessor relies on records rather than direct examination, this should be made explicit.
Key takeaway
Testamentary capacity is the ability to make the specific will in question, judged by the Banks v Goodfellow test at the time of making. It is separate from financial capacity, sensitive to complexity, and best evidenced contemporaneously. A diagnosis alone neither proves nor disproves it.
Frequently asked questions
Is testamentary capacity the same as mental capacity generally?
No. Mental capacity is decision-specific, and testamentary capacity is the particular ability to make a valid will. It has its own legal test in Banks v Goodfellow. A person can have capacity for some decisions and not others, so a general statement that someone has or lacks capacity does not answer the testamentary question.
Who can assess testamentary capacity?
There is no single profession with exclusive authority. Suitably trained doctors, psychiatrists, social workers and capacity specialists can assess it, provided they understand the Banks v Goodfellow test and apply it properly. For elderly or unwell testators, the Golden Rule encourages the involvement of a medical practitioner.
Can a person with dementia make a valid will?
Often, yes. Dementia varies in severity and effect, and many people retain the ability to make a straightforward will, particularly in the earlier stages. The question is whether the condition prevented the testator from meeting the test for that particular will at the time it was made, not whether a diagnosis exists.
Related mental capacity assessment pages
These internal links help readers move from this guide to the most relevant Nellie Supports service page, assessment option or legal framework page.
Considering a testamentary capacity assessment?
Nellie Supports carries out independent testamentary capacity assessments across England and Wales, applying the correct legal test and producing reports fit for solicitors and the courts. To discuss a will that is unusual, late or likely to be contested, see our Testamentary Capacity Assessment service or the Mental Capacity Assessments hub.