Can You Make a Will With Dementia UK (2026)? Capacity, Validity and Options

Yes — a person with dementia can make a valid will, provided they have testamentary capacity at the time they execute (sign) the will. A diagnosis of dementia is not the same as a loss of testamentary capacity. The law assesses capacity on a decision-specific, time-specific basis: the question is not whether you have dementia, but whether you had the required understanding at the specific moment you signed the will. THE BANKS v GOODFELLOW TEST (1870): the classic test for testamentary capacity in English law requires the testator to: (1) Understand the nature of making a will and its effects — that they are creating a document that will distribute their property when they die; (2) Understand the extent of the property they are disposing of — they do not need a precise knowledge of every item, but a general understanding of their assets; (3) Understand and appreciate the claims of those who might reasonably expect to benefit from the estate — they do not need to benefit these people, but they must have an awareness of who they are (family members, dependants, long-term partners); (4) Not be suffering from any 'disorder of the mind' that poisons their affections, perverts their sense of right, or prevents the exercise of their natural faculties in disposing of their property — this fourth element is about whether a mental disorder is directly influencing the content of the will in an abnormal way. The test is functional, not diagnostic: someone with dementia may retain all four elements during a good period, while someone without a formal diagnosis may lack them due to another condition. Many people in the early stages of dementia — including early Alzheimer's disease — retain full testamentary capacity for a considerable period after diagnosis.

The 'Golden Rule' is professional guidance for solicitors taking instructions from elderly or seriously ill clients where testamentary capacity may be in doubt. It was articulated by Templeman J in Kenward v Adams [1975] CLY 3591 and subsequently confirmed in Re Simpson [1977] and other cases: THE RULE: when a solicitor is asked to prepare a will for an aged testator or for a testator who is seriously ill, the solicitor should have the testator medically examined and should ensure that the medical practitioner who examines the testator: (a) is aware of the Banks v Goodfellow test; (b) makes a contemporaneous (same-day or very close to the same day) record of their opinion that the testator satisfies it; and (c) witnesses the execution of the will or is present when it is executed. THE PURPOSE: a contemporaneous medical assessment of capacity is far more reliable than evidence gathered after death (when the will is being challenged). A GP or consultant who examined the testator on the day of execution and recorded their findings provides evidence that is very difficult to contradict. Without this, a will challenge based on incapacity relies on retrospective evidence (care records; family testimony; later assessments) which is inherently uncertain. PRACTICAL IMPLICATIONS: (1) If you or a family member is seeking to make a will after a dementia diagnosis, the first step is a GP assessment of testamentary capacity; (2) The GP should be told about the Banks v Goodfellow test and asked to record their findings; (3) The assessment should be done as close to the signing of the will as possible — ideally the same day; (4) Ideally, the GP should be present when the will is executed or should witness it; (5) The GP's contemporaneous notes form part of the medical record and can be obtained as evidence in later litigation; LIMITATION: the Golden Rule is a professional best practice, not a legal requirement. A will made without medical assessment is not invalid for that reason. However, without contemporaneous medical evidence, a challenge to the will on grounds of incapacity is much harder to defend. For wills where incapacity is likely to be raised — elderly clients, dementia diagnoses, progressive neurological conditions — following the Golden Rule is essential.

A lucid interval is a period during which a person who otherwise lacks mental capacity regains sufficient understanding to perform a legally significant act. English law recognises that someone may lack general capacity most of the time but retain capacity during specific periods of clarity: (1) THE LEGAL PRINCIPLE: a will made during a lucid interval by a person who ordinarily lacks testamentary capacity is valid. The question is whether the testator had capacity AT THE MOMENT of execution — not whether they had capacity the day before, the day after, or on average. This is confirmed in Banks v Goodfellow itself, which discusses 'intervals of perfect sanity'; (2) FLUCTUATING CONDITIONS: some types of dementia, particularly in the early and middle stages, produce fluctuating capacity — the person has 'good days' and 'bad days'. On good days, they may fully satisfy the Banks v Goodfellow test. A will executed on a good day is valid; (3) PRACTICAL APPLICATION: if a family member with early dementia wants to make a will, the best approach is: (a) Choose a good day — when the person appears clear, oriented, and engaged; (b) Involve a GP on the same day — have a medical assessment immediately before signing; (c) Involve a solicitor — who can take instructions, assess capacity through the interview process, and provide a written note of their own observations; (d) Video record the execution if there is significant concern — video evidence of a testator appearing alert, coherent, and understanding what they are signing can be powerful evidence in a later challenge; (4) UNDUE INFLUENCE IN DEMENTIA CASES: where someone is in the late stages of dementia and their affairs are managed by a close relative or carer, courts are alert to the risk of undue influence — pressure applied to the testator to make the will in a particular way. Undue influence requires proof on a balance of probabilities that: (a) the testator was susceptible to influence; (b) pressure was applied; (c) the will reflects that pressure rather than the testator's own wishes; (5) KEY EVIDENCE IN CAPACITY CHALLENGES: GP records; care home notes; hospital records; the solicitor's file notes; observations of professional witnesses; any video recordings of the execution.

If a person has progressed to a stage of dementia where they no longer satisfy the Banks v Goodfellow test — they cannot understand their property, their family, or the nature of making a will — then they cannot make a valid will. At this point, the available options are limited: (1) STATUTORY WILL (COURT OF PROTECTION): the Court of Protection (COP) has jurisdiction under Mental Capacity Act 2005 ss.16-17 to make a statutory will on behalf of a person who lacks testamentary capacity (known as 'P'). The application is made by: (a) a deputy (court-appointed decision maker); (b) an attorney acting under an LPA; (c) a family member or anyone with sufficient interest. The COP will appoint a litigation friend for P, obtain medical evidence of incapacity, consider representations from all interested parties (family members who might benefit or lose), and make the will it considers P would have made if they had capacity. This is a formal and expensive process — legal costs of £5,000-20,000+ depending on complexity. A statutory will must comply with the formal requirements of the Wills Act 1837 s.9 (signed on behalf of P by the authorised person; two witnesses). It has the same effect as a will made by P; (2) INTESTACY IF NO ACTION IS TAKEN: if the person dies without a statutory will (and no existing valid will), the estate passes under the intestacy rules (AEA 1925). The intestacy outcome may be very different from what the person would have wished; (3) EXISTING VALID WILL: if the person made a valid will before they lost capacity, that will remains valid and takes effect on death. The loss of capacity after execution does not invalidate a will made when capacity was present; (4) EXISTING LPA: an attorney under a registered P&FA LPA can manage the incapacitated person's finances. However, the attorney cannot make a will on the donor's behalf — only the COP can do that via a statutory will; (5) WHY ACTING EARLY IS CRITICAL: the difference between early-stage dementia (where a will can still be made) and late-stage dementia (where a statutory will is needed) is a matter of months to years. The cost and distress of a COP statutory will application (many thousands of pounds; court proceedings; invasive medical assessments) vastly outweigh the cost of making a will early. The strongest advice: make a will at the first signs of cognitive decline, not when a diagnosis is received.

A person with early-stage dementia who wishes to make a will should almost always use a solicitor rather than a DIY will kit: (1) THE CASE FOR A SOLICITOR: (a) The solicitor takes detailed attendance notes of the instruction meeting — noting the testator's appearance, coherence, ability to recall information, and understanding of what they were doing. These notes are contemporaneous evidence of capacity that a DIY process cannot provide; (b) The solicitor can apply the Banks v Goodfellow test through the interview process and flag concerns; (c) The solicitor can refer for a medical assessment (Golden Rule) and ensure it is done contemporaneously; (d) The solicitor can advise on the risk of undue influence if a family member is present — and if appropriate, take instructions from the testator alone; (e) If the will is later challenged, the solicitor's file is the primary evidence of what happened and why; (2) THE LIMITATION OF A DIY KIT: a DIY will kit does not involve a professional who can observe and record the testator's capacity. If the will is challenged after death, there is no contemporaneous professional record of the testator's state of mind at the time of execution. This does not make the DIY will invalid — a will executed correctly under WA 1837 s.9 is valid regardless of how it was produced — but without professional contemporaneous evidence, a challenge based on incapacity is harder to resist; (3) WITNESSING: both a DIY will and a solicitor-drafted will must be signed and witnessed by two adult, independent witnesses simultaneously in the presence of the testator. The witnesses observe the testator's behaviour and demeanour at execution — their evidence about the testator's apparent state of mind may be significant in a later challenge. Choose witnesses who are reliable, independent, and likely to be available to give evidence years later; (4) COST: a solicitor will for an elderly person with capacity concerns costs £300-600+. A WillSafe UK will kit starts from £39.99. The solicitor's cost is justified in dementia cases because of the evidential value of their professional file. The kit may be appropriate for someone with very early-stage dementia, clear capacity, and limited family complexity — but professional involvement is strongly recommended wherever capacity is in doubt.