GUIDES
Complex assets do not automatically remove testamentary capacity. The assessment considers the person’s broad understanding of their own estate and proposed will under Banks v Goodfellow.
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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Complex assets do not automatically remove testamentary capacity. The assessment considers the person’s broad understanding of their own estate and proposed will under Banks v Goodfellow. The sections below explain the evidence, practical steps and limits of the assessment or process.
Testamentary capacity requires understanding the extent of the estate in broad terms, not accountancy-grade precision, and that principle is what makes assessment workable for clients with trusts, business interests, cross-border assets and layered structures. The assessment focuses on whether the person broadly grasps what they own, what is actually theirs to leave, who might expect to benefit and the effect of the will they propose. Complexity raises the preparation the assessment needs, not the legal bar the person must meet. This guide explains how assessments handle complex structures and what advisers should prepare in advance.
A person does not need to understand every technical detail of a trust deed, business account or foreign property arrangement. However, the more complex the estate, the more carefully the assessor must identify what the person needs to understand in broad terms to make a valid will decision.
For a person’s own will, apply each limb of Banks v Goodfellow. Consider understanding of the will and its effects, the broad extent of property, appreciation of relevant claims and whether a disorder of mind causes a disposition the person would not otherwise make. A diagnosis or disagreement alone is insufficient. Explain legally complex structures in accessible, salient terms without turning the assessment into a test of tax or trust-law expertise.
Trust complexity may involve beneficial interests, trustees, life interests, discretionary beneficiaries, letters of wishes and whether assets are actually part of the person’s estate. Business complexity may involve shares, partnerships, directorships, trading risk, succession planning, dependent employees and family control. The assessment should not treat these as the same problem.
Where overseas assets are involved, the assessor should not provide foreign succession advice. However, the report may need to record that the person has a broad understanding that property or interests exist outside England and Wales, that different rules may apply, and that professional legal advice has been taken or is needed.
In complex financial cases, the assessor usually needs a concise solicitor-prepared summary rather than a large unsorted bundle. The summary should explain the proposed will, previous wills, asset categories, potential beneficiaries, excluded people, trusts, business interests, overseas assets and any known dispute or undue influence concern.
Some estate structures are legally complex but can still be explained in a way the person understands. The report should distinguish complexity caused by legal drafting from difficulty caused by impairment, confusion, memory problems or inability to weigh competing claims.
Complex financial structures can create dependency on advisers, relatives or business partners. The assessor should consider whether the person has access to independent information, whether someone else controls documents, and whether the person can explain the decision in their own words.
A strong report should identify each source of complexity, explain what was simplified for the person, record the person’s own explanation, consider potential beneficiaries and exclusions, and state clearly whether missing information limits the opinion.
Trusts, businesses and cross-border assets should not be grouped together as generic financial complexity. Each creates different relevant information, different risks and different evidence needs. A good testamentary assessment makes those differences clear.
Yes. Complexity does not automatically prevent capacity. The question is whether the person can understand and weigh the relevant information at the level needed for their will decision, with appropriate support and explanation.
Usually, they need a broad understanding of the extent and nature of their estate rather than precise valuations for every asset. In complex cases, approximate values, asset categories and the practical effect of the will may be more important than exact figures.
Trusts may affect which assets are available to leave and what interests or expectations others hold. Businesses may raise issues about shares, succession or control. Ask the solicitor to identify what belongs to the person’s estate and the practical effect of the proposed will, then explore the person’s broad understanding with appropriate support.
The related pages below explain connected decisions, evidence requirements and legal processes.
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