Writing a Will When Ill UK (2026): Terminal Illness, Urgency & Mental Capacity
Updated 13 May 2026 · 8 min read · England & Wales
A serious illness or terminal diagnosis can make writing a will feel urgent — and it is. An illness does not take away your legal right to make a will; physical frailty is not the same as losing mental capacity. This guide explains the legal requirements, how to act quickly, and how to protect your will from being challenged after your death.
Illness does not take away your right to make a will
A will is valid as long as you have testamentary capacity — the legal standard of mental fitness for making a will, set out in the landmark case Banks v Goodfellow (1870). Physical illness, pain, hospitalisation, and medication do not remove testamentary capacity unless they also impair your mental function.
Many people with serious illnesses — including cancer, heart failure, and even early-stage dementia — retain full testamentary capacity for extended periods. The law does not require you to be in perfect health; it requires you to be mentally capable of making the decisions a will requires.
The Banks v Goodfellow testamentary capacity test
You have testamentary capacity if, at the moment of signing the will, you:
- Understand what a will is and what the effect of signing it will be
- Know the general extent of your estate — broadly what you own, even if you do not know the precise value
- Understand who might reasonably expect to benefit — your spouse, children, other close relatives or dependants
- Are not suffering from a disorder of the mind that causes you to make irrational decisions about who to include or exclude from your will
Being on strong pain medication, being in hospital, or being physically weak does not automatically mean you lack testamentary capacity. Courts look at the specific condition at the specific time of signing.
How to make an urgent will when ill
Option 1: Call a solicitor and request a home or hospital visit
Most solicitors can prepare and execute a will at home or in hospital at short notice. The process:
- Call a local solicitor and explain the urgency and medical situation.
- Give a brief telephone briefing on your wishes — the solicitor will prepare a draft.
- The solicitor visits, goes through the draft with you to confirm your understanding, and — if satisfied about capacity — witnesses your signature together with a second witness (often a colleague or a nurse).
- The will is executed in one visit.
A solicitor’s attendance note recording their assessment of your capacity at the time of signing is extremely valuable if the will is ever challenged. Ask the solicitor to record their observations about your mental state explicitly in the file.
Option 2: DIY will kit for immediate use
If time is very short or a solicitor is not immediately available, a DIY will kit can be completed quickly at home or in hospital. Key points for an urgent handwritten or kit-based will:
- Keep the wording simple and unambiguous — complicated arrangements can be handled later
- Include: a revocation clause, executor appointment, and a clear residuary gift (“everything else to [person]”)
- Sign clearly at the end, in the presence of two independent adults who do not benefit from the will
- Witnesses sign immediately, in your presence, at the same time as each other
- Date the will
A simple, correctly executed will is always better than no will. Even a handwritten document meeting the s9 formalities is fully valid.
Option 3: request a GP capacity assessment
If there is any risk that the will could be challenged on capacity grounds — for example, if you have received a diagnosis of dementia, are on heavy sedation, or have relatives who might dispute the will — arrange a formal capacity assessment from your GP or a psychiatrist contemporaneous with or immediately before signing.
A capacity assessment stating that you understood the nature and effect of the will at the time of signing provides very strong evidence against a later challenge. Ask the GP to note:
- That you understood what a will is and what you were signing
- That you knew the extent of your estate
- That you understood who might reasonably claim on your estate
- That you were not under undue influence
What is a deathbed will?
A deathbed will is a will made in the final stages of a terminal illness, often in the last days or hours of life. It is fully valid in England and Wales provided the s9 Wills Act 1837 formalities are met. The challenges are:
- Finding two independent witnesses quickly
- Ensuring the testator can physically sign (or direct someone to sign in their presence)
- Demonstrating testamentary capacity at that precise moment
Where a testator cannot hold a pen, the will can be signed by another person at the testator’s direction, in their presence — but the person signing must not be a beneficiary. This is sometimes done with a nurse or carer present.
Protecting the will from challenge
A will made when the testator is seriously ill is more vulnerable to challenge on capacity or undue influence grounds. Steps to protect it:
- Use a solicitor who prepares a contemporaneous capacity note
- Obtain a GP capacity letter at or around the time of signing
- Ensure the will was not prepared or witnessed by beneficiaries or close relatives of beneficiaries
- Instruct the solicitor independently — if a beneficiary arranges the solicitor visit and is present throughout, this creates an undue influence risk
- Keep a record of the testator’s expressed wishes over time (previous conversations, earlier draft wills) to show the will reflects consistent wishes
- Do not make radical last-minute changes that depart significantly from earlier expressed intentions without a clear reason
What if capacity is lost before a will is signed?
If a person permanently loses testamentary capacity before they have made a will, no one else can make a will on their behalf. The only option is to apply to the Court of Protection for a Statutory Will — an order authorising someone to execute a will on behalf of the incapacitated person, based on evidence of what they would have wanted. Statutory Will applications are expensive (typically £5,000–£15,000+), slow (6–18 months), and not always granted. This underlines why it is so important to make or update a will as early as possible after any serious diagnosis.
Frequently asked questions
Can I make a will if I have been diagnosed with a terminal illness?
Yes — a terminal illness diagnosis does not affect your legal capacity to make a will. You can make a valid will at any point while you still have testamentary capacity under the Banks v Goodfellow test: you understand the nature of a will and its effects, the extent of your estate, the people who might reasonably expect to benefit, and the claims they may have. Many people with terminal diagnoses have months or years in which they retain full capacity. Do not delay.
What is testamentary capacity and how is it assessed?
Testamentary capacity is the legal standard for mental fitness to make a will, set out in Banks v Goodfellow (1870). You must: (1) understand what a will is and what signing it means; (2) know the general nature and extent of your estate; (3) understand who might have a reasonable claim on your estate (e.g. spouse, children); (4) not be suffering from a disorder of the mind that causes you to exclude people you would otherwise include, or include people you would otherwise exclude. Physical illness and pain do not affect capacity unless they impair mental function.
What is a deathbed will and is it valid?
A deathbed will is a will made in the final days or hours of life. It is valid in England and Wales provided it meets the same requirements as any other will: in writing, signed by the testator (or at their direction in their presence), witnessed by two independent adults present simultaneously. The main risk is that the testator's deteriorating condition raises questions about testamentary capacity, making the will vulnerable to challenge after death. A doctor's capacity assessment or a solicitor's attendance note contemporaneous with signing provides strong evidence that capacity was present.
What is a soldier's or privileged will?
Under s11 Wills Act 1837, a soldier in active military service or a mariner at sea can make an informal will — oral (spoken), handwritten without witnesses, or in any other form — that is legally valid without the usual witness requirements. The exemption applies only during actual service. This is a narrow exception; most people in hospital or at home with a terminal illness cannot use it. Civilian patients must use the standard s9 formalities.
How can I make a will urgently when I am ill?
Contact a solicitor immediately and explain the urgency. Most solicitors will: (1) visit the patient at home or in hospital; (2) prepare a draft will quickly based on a telephone briefing; (3) arrange for two independent witnesses at the bedside. Many law firms have an emergency wills service for exactly this situation. Alternatively, a DIY will kit can be completed at home quickly — the key is to keep the wording simple, sign it clearly, and have two independent witnesses present. Speed matters more than perfection when time is short.
What happens if a will is challenged on capacity grounds?
A will can be challenged after the testator's death on the grounds of lack of testamentary capacity (or undue influence). The burden of proof is on the challenger. Evidence that supports the will's validity: a GP's capacity assessment made at the time of signing; a solicitor's attendance note; a lucid execution with witnesses; a will that reflects the person's expressed wishes over time. Evidence that helps challengers: medication affecting cognition, a diagnosis of dementia, a will that radically departs from previous instructions, or a will made when alone with one beneficiary.
Can I make a will if I have dementia?
Yes, but only during a 'lucid interval' — a period when the person has sufficient clarity to meet the Banks v Goodfellow test. People in early-stage dementia often retain full testamentary capacity for years. A professional capacity assessment from a GP or psychiatrist contemporaneous with the signing of the will is strongly advisable and makes any later challenge very difficult. Once capacity is permanently lost, only the Court of Protection can authorise a Statutory Will on behalf of the individual — an expensive and slow process.
Don't wait — make your will today
WillSafe’s DIY will kit can be downloaded, completed, and signed in under an hour. If you are seriously ill and time is short, a simple correctly-executed will is far better than no will at all.
Get the will kit →Related guides
- Testamentary capacity explained
- Undue influence and wills
- Handwritten wills — are they valid?
- When to update your will
- Lasting Power of Attorney — why it matters alongside a will