Author and Publication
Author: Nellie Supports Ltd
Publication Date: 15/05/2026
Citation
Mental Capacity Act 2005, c. 9. Available at: https://www.legislation.gov.uk/ukpga/2005/9/contents
Copywright
Copyright © 2026 Nellie Supports Ltd. All rights reserved.
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Undue influence and testamentary capacity assessments
Undue influence and lack of testamentary capacity are different legal challenges to a will, and they are often confused. Capacity asks whether the person could understand the nature of a will, their estate in broad terms and the claims of potential beneficiaries. Undue influence asks whether pressure overpowered a capable person's free will. A person can have full capacity and still be unduly influenced, or lack capacity with no influence at all. A well-run capacity assessment addresses both risks: it evidences the legal test and records the private, uncoached account that makes influence easier to prove or disprove later. This guide explains the distinction and the evidence each challenge requires.
Capacity and undue influence are different questions
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.
Capacity and undue influence are different questions
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.
What the assessor can and cannot decide
The assessor can record observations, identify risk factors, explain whether the person could understand and weigh the relevant information, and comment on whether the assessment conditions were affected by pressure. The assessor should not present themselves as deciding a contested legal claim of undue influence unless specifically qualified and instructed to provide that legal opinion.
Common risk features
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.
Assessment conditions should reduce pressure
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.
How to record the person’s own reasoning
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.
When enhanced assessment is safer
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.
What a report should say about limitations
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.
Key takeaway
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.
Frequently asked questions
Is undue influence the same as lack of testamentary capacity?
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.
Can a testamentary assessment identify undue influence concerns?
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.
Should the proposed beneficiary be present?
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.
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.
Concerned about capacity, influence or both?
Nellie Supports completes testamentary capacity assessments across England and Wales, prospective, contemporaneous and retrospective, through a permanent employed team with every report peer reviewed before delivery. Call 0333 987 5118 or visit the testamentary capacity assessment service page.