GUIDES
Testamentary capacity and undue influence are distinct legal issues. A capacity opinion can record relevant observations, but a disputed claim of undue influence is for the court.
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 and undue influence are distinct legal issues. A capacity opinion can record relevant observations, but a disputed claim of undue influence is for the court. The sections below explain the evidence, practical steps and limits of the assessment or process.
A will may be questioned for lack of testamentary capacity, undue influence or other validity issues. Banks v Goodfellow concerns capacity for the will; undue influence concerns coercion overcoming the testator’s free will. A person with capacity can be coerced. A capacity assessor can document a private account and relevant observations, but cannot guarantee that influence will be proved, disproved or prevented.
Testamentary capacity asks whether the person has the ability to make the will decision. Undue influence concerns whether the person’s free decision-making has been overborne by pressure or coercion. The two issues can overlap in evidence, but they should not be treated as the same legal question.
Testamentary capacity asks whether the person could make the will, applying Banks v Goodfellow. Undue influence asks whether the will, however capacitously made, reflects coercion rather than the testator's own free judgement. A person with full capacity can be unduly influenced, and a person free of any pressure can lack capacity. The two questions are assessed differently and challenged differently in probate, and an assessment that conflates them weakens the evidence on both.
The assessor can give an opinion within their expertise on testamentary capacity and document observed or reported concerns, clearly identifying the source and limits. A contested undue-influence claim is ultimately a legal question for the court. Do not label a person’s relative as coercive on the basis of a risk feature or capacity interview alone.
Risk features may include isolation, dependence on a beneficiary, fear of withdrawal of care, sudden changes to a will, exclusion of close relatives, secrecy, controlling behaviour, restricted access to professional advice, recent bereavement, cognitive decline or a beneficiary arranging and managing the assessment.
The assessment should normally take place in private, with care taken over who arranges the appointment, who provides information, who is present, how the person communicates and whether they can explain their own wishes without prompting. Any departure from this should be recorded and explained.
The report should capture the person’s own explanation for the proposed will, including why certain people are included, excluded or treated differently. The assessor should consider whether the explanation appears to be understood, retained and weighed by the person or simply repeated from someone else.
Enhanced assessment may be safer where there is family conflict, a large estate, a new beneficiary, late-life changes, cognitive impairment, dependence on one relative, alleged coercion, communication barriers or a risk that the will is likely to be challenged after death.
If the assessor has not seen earlier wills, full estate information, medical records or solicitor notes, the report should say so. If the person was not assessed privately or if information came mainly from a beneficiary, that limitation should also be explained.
Undue influence concerns make testamentary capacity assessment more delicate, not impossible. The safest report separates capacity from influence, records risk factors carefully and explains how the person’s own understanding and reasoning were tested.
No. A person may have testamentary capacity but still be subject to undue influence. A person may also lack capacity without any undue influence. The assessment should keep the two questions separate while recognising that some evidence may be relevant to both.
Yes. A careful assessment can identify concerns such as pressure, dependency, inconsistent explanations, inability to speak privately, fear of a beneficiary or instructions that appear to be controlled by someone else. Those concerns should be recorded clearly and neutrally.
Usually not during the substantive assessment, especially where undue influence is suspected. The person should be able to explain their wishes privately. If anyone else is present, the report should explain why and how this may have affected the assessment.What evidence helps where undue influence is alleged?Helpful evidence may include previous wills, solicitor notes, medical records, care records, communication records, family history, evidence of dependence, details of who arranged the will, who gave instructions and whether the person had independent advice.
The related pages below explain connected decisions, evidence requirements and legal processes.
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