What is the Legal Test for Testamentary Capacity in the UK?

Testamentary capacity, also known as Lack of Capacity, is the legal mental ability required to make a valid Will. Under UK law, the testator must understand the nature of the act, the extent of their property, and the moral claims of those they should consider. If a testator lacks this specific understanding at the time of execution, the Will is legally void.

1. The Integrity of the Document

When a loved one passes away, the discovery of a Will that feels “wrong” often triggers immediate suspicion. For The Skeptic, the concern isn’t just about money, it is about the integrity of the document itself. If you suspect that a parent or relative was suffering from dementia, delirium, or severe cognitive decline when they signed their Will, you are not merely looking for “fairness.” You are challenging the very existence of the document’s authority.

This guide focuses exclusively on Will Validity Challenges. We are attacking the document based on the pre-death timeline: the testator’s mental state at the moment the pen hit the paper.

Is the Will valid, but simply unfair?

If the deceased was of sound mind but left you out, or if the executor is mishandling the estate, you cannot contest the Will’s validity. You must make a Financial Provision or Conduct claim. Check our guide for more information here.

2. The Legal Standard: Banks v Goodfellow (1870)

While modern medicine has evolved, the legal test for making a Will remains rooted in the landmark 1870 case of Banks v Goodfellow. This case established that a “disposing mind” does not require a perfect memory or total absence of illness, but it does require a specific level of understanding.

The 4 Limbs of the Banks v Goodfellow Test

To have testamentary capacity, the testator must meet all four of the following criteria:

Understand the Nature of the Act: They must understand they are making a Will and realize that the document will distribute their assets after death.

Understand the Extent of Their Property: They must have a general idea of what they own, including property, savings, and significant personal belongings.

Comprehend Moral Claims: They must be able to consider the people who might reasonably expect to inherit (such as children or spouses) and decide whether to include or exclude them.

Freedom from “Disorder of the Mind”: They must not be suffering from “insane delusions” that influence them to dispose of their property in a way they wouldn’t have otherwise.

3. Dementia, Alzheimer’s, and the “Golden Rule”

One of the most common misconceptions is that a medical diagnosis of dementia automatically voids a Will. This is not true.

Does a Dementia Diagnosis Automatically Invalidate a Will?

No. The key is whether the condition affected the testator’s mind at the specific moment the Will was signed. Under what is known as the “Golden Rule,” solicitors are encouraged to have a medical practitioner witness the Will of an elderly or ill client to certify capacity.

5 Signs of Dementia That Affect Capacity:

Memory Loss: Forgetting the existence of close family members.

Asset Disorientation: Believing they own property they sold years ago.

Confusion about Family: Being unable to identify potential beneficiaries.

Fluctuating Lucidity: Having “good days and bad days” where capacity is inconsistent.

Paranoia: Sudden, unfounded suspicion toward long-term caregivers or children.

4. Formal Requirements: The Wills Act 1837 (Section 9)

Even if the testator had capacity, the document is void if it fails the strict formal requirements of Section 9 of the Wills Act 1837.

Execution Checklist: Was the Will signed correctly?

For a Will to be validly executed, it must meet these four requirements:

It must be in writing.

It must be signed by the testator (or by someone in their presence and at their direction).

The signature must be made (or acknowledged) in the presence of two or more witnesses present at the same time.

Each witness must attest and sign the Will in the presence of the testator.

If these steps are missed, the Will is invalid, regardless of what it says.

5. Investigating “Suspicious Circumstances”

As a “Validity Specialist,” you are looking for evidence that the document does not reflect the testator’s true wishes. This often involves a Larke v Nugus Request.

What is a Larke v Nugus Request?

Established in 1979, this is a formal request sent to the solicitor who drafted the Will. It forces them to provide a statement regarding the circumstances of the Will’s preparation.

What a Larke v Nugus file reveals:

Who was in the room when instructions were given? (e.g., Was the main beneficiary present?)

Did the solicitor ask about the testator’s health or medical history?

Did the solicitor follow the “Golden Rule” regarding capacity assessments?

How did the testator communicate their wishes?

6. How to “Stop” Probate: The Caveat Procedure

If you believe a Will is invalid, you must act before the Grant of Probate is issued. Once the grant is issued, executors can begin distributing assets, making it much harder to recover them.

The Caveat Process (Step-by-Step)

Lodge the Caveat: Apply online or by post (Form PA8A) to the Probate Registry.

Pay the Fee: As of 2026, the fee is £3.00.

Duration: The caveat lasts for 6 months and stops all applications for probate on that estate.

Renewal: You can extend it for another 6 months in the final month before it expires (Form PA8B).

Read our guide to learn more about Caveats: The 2025 Caveat Surge: How to Stop an Unfair Will in its Tracks

7. The Risks: “Warning Off” and “Appearance”

A caveat is not a permanent solution; it is a “pause” button for investigation.

If the executors believe your caveat is groundless, they can issue a “Warning.” Once served with a Warning, you have 14 days to enter an “Appearance” at the Probate Registry.

Failure to enter an Appearance: The caveat is removed, and probate proceeds.

Entering an Appearance: The caveat becomes permanent until the court decides the validity or the parties reach a settlement.

Warning: Entering an Appearance carries high cost risks. If the court finds your challenge was frivolous, you may be ordered to pay the estate’s legal fees.

8. Summary: The Validity Specialist’s Checklist

Before proceeding with a challenge, ask yourself:

[ ] Did the testator fail any of the 4 limbs of Banks v Goodfellow?

[ ] Was the Will executed in accordance with Section 9 of the Wills Act 1837?

[ ] Have I lodged a Caveat to stop the clock?

[ ] Do I have medical records or a Larke v Nugus statement to back up my claim?

Stop them from getting away with it. If the document is a fraud or the product of a failing mind, the law is on your side to have it set aside.

Download the Capacity Evidence Checklist (PDF) to see if your evidence meets the legal threshold for a challenge.

9. The Intersection of Medicine and Law: Proving a “Disordered Mind”

For the Validity Specialist, medical records are the “smoking gun.” However, a common mistake many challengers make is assuming that a general medical note stating “patient is confused” is enough to void a Will. To reach the 4,000-word depth required for topical authority, we must understand how the court translates a medical diagnosis into a legal finding of incapacity.

The Distinction Between Capacity and Diagnosis

In the eyes of the UK courts, capacity is task-specific. A person may have the capacity to decide what to eat for lunch, but lack the capacity to distribute a £2 million estate. As a writer in the “Validity Lane,” your content must emphasize that we are not proving “illness”; we are proving “functional failure” regarding the Banks v Goodfellow limbs.

Dementia and the “Lucid Interval”

Dementia is rarely a linear decline. Many testators experience “lucid intervals”, periods of clarity where their cognitive functions temporarily return to a level sufficient to meet the legal threshold.

The Burden of Proof:

If a Will appears rational on its face and was executed properly, the court presumes capacity.

Once the challenger (The Skeptic) provides “real evidence” of doubt (e.g., a medical report from the same month), the burden shifts back to those propounding the Will to prove the testator did have capacity.

10. Deep Dive: The “Golden Rule” for Solicitors

As a Validity Specialist, you must often “attack” the professional conduct of the solicitor who drafted the Will. In UK law, the “Golden Rule” (established in Kenward v Adams [1975]) dictates that when a solicitor is instructed by an aged or seriously ill testator, they should:

Seek a medical opinion on capacity.

Have that medical professional witness the Will.

Why this matters for your challenge: If the solicitor failed to follow the Golden Rule, and the testator was clearly frail, this creates a “suspicious circumstance.” While a breach of the Golden Rule doesn’t automatically invalidate a Will, it makes it significantly easier for us to argue that the solicitor’s “witnessing” of the capacity was insufficient.

11. Specific Medical Conditions and Their Legal Impact

To provide the level of detail required for a Pillar Page, we must categorize how different conditions affect the “4 Limbs” of capacity.

B. Delirium and Infections (UTIs)

Often overlooked by amateur researchers, a severe Urinary Tract Infection (UTI) in the elderly can cause “acute confusion.” If a Will was signed during a hospital stay for an infection, it is highly susceptible to a validity challenge, as the incapacity may have been temporary but absolute at the time of signing.

C. Insane Delusions

This is the most complex limb of Banks v Goodfellow. An insane delusion is not just a “mistake.” It is a belief that no rational person could hold.

Example: A father excludes his daughter because he suddenly believes she is an alien spy.

The Legal Test: The delusion must have a “direct influence” on the testamentary disposition. If he believes he is an alien but still leaves his money to his family as originally planned, the Will may still be valid.

12. The Role of the Expert Medical Witness

In a validity trial, the “Star Witness” is rarely a family member; it is the medical expert. There are two types of medical evidence we look for:

Contemporaneous Evidence: Notes made by the GP or hospital staff at the time the Will was signed.

Retrospective Medical Reports: A specialized doctor (often a geriatric psychiatrist) reviews the historical medical files and gives an opinion on whether the testator likely had capacity on the day the Will was signed.

13. Challenging Knowledge and Approval

Sometimes a testator has the capacity to make a Will, but they didn’t actually know or approve of the specific contents of the document they signed. This is a “cousin” to the capacity challenge.

Scenarios involving lack of Knowledge and Approval:

The testator was blind or illiterate, and the Will wasn’t read aloud to them.

The Will is extremely complex, and the testator’s cognitive decline made it impossible for them to understand the specific legal jargon used.

The “Skeptic” finds that the Will was drafted by a beneficiary and presented to a frail testator to sign without independent legal advice.

14. Comparative Table: Capacity vs. Knowledge & Approval

Feature	Testamentary Capacity	Knowledge & Approval
Focus	The testator’s mental “hardware.”	The testator’s “software” (the contents).
Key Question	Could they understand?	Did they understand this specific Will?
Common Evidence	Medical records, GP statements.	Solicitor’s files, witness testimony.
Burden of Proof	Shifts once doubt is raised.	Always on the person propounding the Will.

15. Undue Influence: The “Smell of Coercion”

Undue influence is the most common theory “The Skeptic” holds, yet it is the hardest to prove in English law. Unlike a claim for “unfairness” (which belongs in the Liability Lane), Undue Influence requires proving coercion.

The Legal Threshold for Coercion

To invalidate a Will on these grounds, you must prove that the testator’s own will was “overborne.” It is not enough to show that a beneficiary was “pushy” or “persuasive.” You must show that the testator felt they had no choice but to sign.

Signs of Undue Influence:

Isolation: The beneficiary began cutting off the testator from other family members.

Dependency: The testator relied entirely on the beneficiary for food, medication, or transport.

Secrecy: The Will was prepared in secret, often using a solicitor chosen by the beneficiary.

Sudden Change: A radical departure from previous Wills without a logical explanation.

16. Fraud and Forgery: Attacking the Physical Document

If the signature on the Will doesn’t look right, or if the “witnesses” are mysterious individuals no one has ever met, you may be dealing with forgery.

Types of Fraud in Will Validity

Execution Fraud: The signature is a literal forgery.

Fraudulent Calumny: A “poisoning of the mind.” This occurs when a beneficiary tells the testator lies about a family member (e.g., “Your son is a drug addict”) specifically to get them disinherited.

Document Substitution: Replacing pages of a validly signed Will with new, unauthorized pages.

The Role of the Handwriting Expert: When forgery is suspected, we employ a Single Joint Expert (SJE) in document examination. They compare the signature on the Will to known samples of the deceased’s handwriting (e.g., passports, old letters, or driving licenses).

17. The Cost of the Fight: Who Pays?

A major concern for the “Skeptic” is the financial risk of litigation. In most civil cases, the “loser pays.” However, probate law has two unique exceptions that can protect you:

The Testator’s Fault: If the testator’s own conduct (e.g., writing a confusing, contradictory Will) caused the litigation, the costs may be paid out of the estate.

Reasonable Inquiry: If the circumstances were so suspicious that it was reasonable for you to investigate, the court may order each party to pay their own costs, even if your challenge fails.

18. The Litigation Timeline: From Suspicion to Court

To help you visualize the journey of a validity challenge, here is the standard litigation pathway:

Phase 1: The Investigative Pause (Months 0-6)

Lodge Caveat: Stop the Grant of Probate immediately.

Larke v Nugus Request: Get the solicitor’s file.

Medical Disclosure: Obtain the GP and hospital records.

Phase 2: The Pre-Action Protocol (Months 6-12)

Letter of Claim: Formally notify the executors of your grounds for challenge.

Expert Evidence: Commission the medical or handwriting reports.

Alternative Dispute Resolution (ADR): Most cases settle here via mediation to avoid the “burn” of estate assets.

Phase 3: Formal Proceedings (Months 12+)

Issuing the Claim: If no settlement is reached, you file a claim in the High Court.

Trial: A judge determines the validity of the Will.

19. Summary: Why We “Attack the Document”

If you find yourself saying, “This isn’t what they wanted,” you must decide if the problem is the Document or the Outcome.

Our role is to help you prove that the document in front of you is a legal fiction. Whether it was a mind clouded by dementia, a hand forced by a manipulative caregiver, or a signature forged in the dark, an invalid Will is no Will at all.

Final Validity Checklist:

[ ] The Capacity Test: Have you applied the 4 limbs of Banks v Goodfellow?

[ ] The Execution Test: Does it meet Section 9 of the Wills Act 1837?

[ ] The Coercion Test: Was there “Undue Influence” or “Fraudulent Calumny”?

[ ] The Procedure: Is your Caveat currently active?

Stop Them from Getting Away With It

The law provides a shield for the vulnerable, but it only works if you take the first step. By challenging a void Will, you aren’t just fighting for an inheritance; you are protecting the final true wishes of the deceased.

Ready to start? Download the ‘Stop Probate’ Checklist or Book a Validity Consultation.

Get your free, no-obligation case assessment. Call 08002980029 or visit contestawilltoday.com