GUIDES
Testamentary capacity is the ability to make the particular will under Banks v Goodfellow. It is distinct from the Mental Capacity Act test and does not alone establish every requirement for a valid will.
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Mental Capacity Act 2005, c. 9. Available at: https://www.legislation.gov.uk/ukpga/2005/9/contents
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Testamentary capacity is the ability to make the particular will under Banks v Goodfellow. It is distinct from the Mental Capacity Act test and does not alone establish every requirement for a valid will. The sections below explain the evidence, practical steps and limits of the assessment or process.
Testamentary capacity is the mental capacity a person needs to make or change a valid will. The test comes from Banks v Goodfellow (1870): the person must understand the nature of making a will and its effects, understand in broad terms the extent of their estate, and appreciate the claims of those who might expect to benefit, with no disorder of the mind distorting their judgement in disposing of it. It is decision-specific: someone may lack capacity for complex financial management and still validly make a will. A careful assessment can provide useful evidence, but it does not prevent later challenge or determine the court or other decision-maker’s conclusion.
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.
Banks v Goodfellow remains the governing common-law test for capacity to make one’s own will in England and Wales. It is distinct from the Mental Capacity Act functional framework used for statutory-will jurisdiction. Capacity is one requirement for a valid will: knowledge and approval, due execution and any allegation of undue influence must be considered separately.
The test remains Banks v Goodfellow for the particular will. A complex structure may require clearer preparation about the broad property, intended effects and possible claims, but high value or family disagreement does not automatically raise the legal threshold. Support understanding of the salient matters without demanding expertise in the will’s technical drafting.
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.
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.
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.
Contemporaneous evidence can preserve the person’s actual understanding and the conditions in which instructions and execution took place. It may assist a later court but does not eliminate the risk of challenge or guarantee validity. Consider appropriate medical involvement under the Golden Rule and retain the solicitor’s detailed notes alongside any independent opinion.
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.
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.
No. Testamentary capacity is a specific legal test from Banks v Goodfellow concerned only with making or changing a will. It is assessed separately from other capacities, so a person may lack capacity to litigate or to manage complex finances and still have testamentary capacity, or the reverse.
A suitably experienced professional: specialist social workers, psychologists, psychiatrists or doctors familiar with the Banks v Goodfellow test and structured capacity assessment. No statute reserves the role to medical practitioners, and courts weigh the quality of the decision-specific reasoning over the assessor's title.
A person with dementia may retain testamentary capacity; assess Banks v Goodfellow at the legally relevant time with suitable support. If validity is later disputed, the court considers the will file, professional and witness evidence, medical and care records and any capacity opinion. No single report has conclusive status or guarantees that the will is upheld.
The related pages below explain connected decisions, evidence requirements and legal processes.
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