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.
This article is made available for general information, education and professional reference. It may be downloaded, printed and shared for non-commercial purposes, provided that it is reproduced in full, is not altered in any way, and is properly cited as the work of Nellie Supports Ltd. This material must not be edited, adapted, sold, republished, incorporated into commercial products, or used for commercial training, assessment, report-writing or advisory services without prior written permission from Nellie Supports Ltd.
This article does not constitute legal advice, clinical advice or a substitute for a decision-specific professional assessment. Where legislation, government guidance, court forms or external professional materials are referred to, those materials remain subject to their own copyright, licensing and re-use terms.
Testamentary capacity versus statutory will applications
Testamentary capacity and statutory wills are the two routes to a valid will, and which applies depends on one question: can the person make the will themselves? A person with testamentary capacity under Banks v Goodfellow makes their own will, however unwise others may think it. Where the person lacks testamentary capacity, the Court of Protection can authorise a statutory will on their behalf under the Mental Capacity Act 2005, decided on their best interests. A capacity assessment therefore sits at the fork in the road: its conclusion determines which route is open. This guide compares the two routes and the evidence each requires.
Two different routes to a valid will
Testamentary capacity and statutory wills are answers to two different situations. Where a person retains testamentary capacity, they make their own will, and an assessment evidences that the will is theirs. Where a person lacks testamentary capacity, they cannot make a valid will at all, and the route to updating their testamentary position runs through the Court of Protection, which can authorise a statutory will on their behalf. Choosing the wrong route wastes months; understanding the distinction at the outset directs the evidence and the application correctly.
The test for making a will
Testamentary capacity is assessed against the test in Banks v Goodfellow. The person must understand the nature of making a will and its effects, understand in broad terms the extent of the property being disposed of, and be able to comprehend and appreciate the claims to which they ought to give effect, and no disorder of the mind should poison their affections or pervert their sense of right so as to influence the disposal. The threshold is not perfection. A testator does not need to recall every asset or value precisely, but they must hold a broad, workable picture of their estate and of the people with claims upon it.
Where capacity is retained: assess, support and record
A diagnosis does not remove testamentary capacity, and many people with dementia or other impairments can still make a valid will, particularly where the estate and intentions are straightforward. In this situation the task is to support the person to make their will and to evidence the capacity contemporaneously, so the will is protected against later challenge. A decision-specific assessment at the time of instructions and, ideally, at execution provides that evidence in a form a probate court can rely upon years later.
Where capacity is lacking: the statutory will route
Where the person cannot meet the Banks v Goodfellow test, a will they sign is open to challenge and the proper route is an application to the Court of Protection for a statutory will under the Mental Capacity Act 2005. The court decides whether to authorise the will and in what terms, applying the best interests framework. Statutory wills are commonly sought where an existing will is badly outdated, where intestacy would produce a result the person would never have wanted, or where the estate has changed substantially since capacity was lost.
The evidence each route requires
The two routes demand different evidence pointing in different directions. Supporting a person to make their own will calls for evidence that capacity is present, assessed against Banks v Goodfellow and recorded in the person's own words. A statutory will application calls for evidence that testamentary capacity is lacking, usually presented to the court on a COP3 alongside evidence about the person's circumstances, their past and present wishes and the estate. The same assessment discipline underpins both: the specific test, the functional analysis and the causative link to an impairment.
Best interests and the person's wishes in a statutory will
A statutory will is not simply what the applicant wants or what a reasonable person would choose. The court weighs the person's best interests in the widest sense, and the person's past and present wishes, feelings, beliefs and values carry substantial weight. Evidence of what the person said and did whilst they had capacity, of earlier wills and of family relationships therefore matters enormously, and an assessment that records the person's current wishes and feelings, even where capacity is absent, contributes directly to the court's analysis.
Timing, deterioration and urgent situations
Timing decides which route remains open. In progressive conditions, a person who retains capacity today may not next year, and acting whilst capacity remains preserves the person's own voice in their will rather than substituting the court's. Conversely, where death is foreseeable and capacity has gone, statutory will applications can be expedited, and the court has procedures for urgency. The worst position is the middle: waiting, in the hope capacity questions resolve themselves, until neither a supported will nor an orderly application is achievable.
Choosing the route in practice
The practical starting point is a contemporaneous, decision-specific testamentary capacity assessment. If capacity is present, the will proceeds with the assessment as its shield. If capacity is absent, the same assessment becomes the foundation of the statutory will application, and nothing is wasted. Solicitors and families who commission the assessment first, rather than presuming the answer in either direction, protect the person, the estate and themselves from the far greater cost of getting the route wrong.
Key takeaway
Testamentary capacity and statutory wills sit either side of a single line: the Banks v Goodfellow test at the time of making the will. A contemporaneous assessment locates the person against that line, and the result directs everything that follows, from a supported, protected will to a properly evidenced Court of Protection application. Assess first, then choose the route.
Frequently asked questions
Does a diagnosis automatically mean someone lacks capacity?
No. A diagnosis may explain why capacity is in doubt, but it does not answer the legal question. The assessment must still consider the specific decision, the relevant information, the support provided and whether the person can understand, retain, use or weigh that information and communicate a decision.
What evidence is useful for Testamentary Capacity Assessment?
For a testamentary capacity assessment, the key materials are the draft or proposed will, previous wills, a broad estate summary and relevant medical records. For a statutory will application, the court additionally requires the Court of Protection forms, evidence about best interests, details of those who might expect to benefit and the proposed will itself.
When is a formal assessment for Testamentary Capacity Assessment useful?
The assessment should come first, before significant costs are incurred on either route. If capacity is present, the person proceeds with their own will and the assessment protects it from later challenge. If capacity is absent, the same properly evidenced assessment becomes the foundation of the statutory will application.
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.
Testamentary capacity or statutory will?
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.