Banks v Goodfellow (1870): Testamentary Capacity Test UK Explained

Banks v Goodfellow [1870] LR 5 QB 549 is the foundational English case on testamentary capacity. The four-part test laid down by Cockburn CJ — understanding the nature of a will, the extent of the estate, the claims of those who might benefit, and the absence of a disorder of mind — remains the law in England and Wales today. This guide explains each limb, how courts apply the test, and the practical steps you can take to protect your will against a capacity challenge.

Background: The Case of John Banks

John Banks suffered from delusions — he believed he was being persecuted by evil spirits and a man named Alexander. He was also epileptic. Despite this, he made a will leaving his property to his niece rather than to his brother (who was also his heir-at-law). After Banks' death, the will was challenged on the grounds that he lacked testamentary capacity.

The Court of Queen's Bench upheld the will. Cockburn CJ held that Banks' delusions did not affect the dispositions in the will — his mind was sound enough to understand what he was doing, what he owned, and who had a claim on his estate. The delusions related to persons who had no connection with the will.

The judgment established a principle that mental illness alone does not destroy testamentary capacity — the question is always whether the specific mental condition affected the specific testamentary act.

The Four-Part Test

Cockburn CJ stated that a testator must, at the time of making the will:

Understand the nature of making a will and its effects — know that the document they are signing is a will, that it disposes of their property on their death, and that it can be changed during their lifetime but takes effect at death.
Understand the extent of the property being disposed of — have a general (not precise) understanding of what they own. A person does not need to know the exact value of their estate; they must know broadly what assets they have.
Understand the claims of those who might expect to benefit — know who has a natural claim on their bounty, typically close family members. The testator does not need to leave anything to those people, but must be aware of their existence and their potential claim, so that any decision to exclude them is informed.
Suffer from no disorder of the mind that poisons their affections, perverts their sense of right, or prevents the exercise of their natural faculties — the mental condition must not have so distorted the testator's thinking that the will is the product of the disorder rather than of free and rational decision-making.

Capacity is assessed at the moment instructions are given and at the moment of execution. Where instructions were given while the testator had capacity but execution occurred later when capacity may have been lost, the will may still be valid if the testator had capacity at the earlier date and did not alter the will before execution.

The Golden Rule and Solicitor Best Practice

When instructed by an elderly or seriously ill testator, solicitors should follow the 'golden rule' from Kenward v Adams [1975]: arrange for a medical practitioner to assess capacity and provide a contemporaneous certificate. Ideally, the doctor attends at execution.

This protects both the testator's intentions and the solicitor against a negligence claim. A failure to follow the golden rule does not invalidate the will, but courts have repeatedly said it increases the risk of a successful challenge.

For a full discussion of testamentary capacity and what solicitors should do at the point of taking instructions, see our dedicated guide.

Lucid Intervals

A person whose mental capacity generally fluctuates — as often happens with dementia, severe depression, or conditions treated with medication — may make a valid will during a lucid interval: a period when their mind is sufficiently clear to satisfy all four limbs of the Banks v Goodfellow test.

Evidence of a genuine lucid interval at the time of execution is typically drawn from contemporaneous medical records, the observations of those present (solicitor, witnesses, GP), and expert psychiatric evidence about the nature of the condition and its typical pattern of fluctuation.

Banks v Goodfellow and the Mental Capacity Act 2005

The Mental Capacity Act 2005 introduced a statutory test for decision-making capacity used in medical, financial, and welfare contexts — but the MCA 2005 does not govern testamentary capacity. The Banks v Goodfellow test continues to apply to wills.

The two tests are not equivalent: a person assessed as lacking MCA capacity for most purposes (for example, managing their finances) may still satisfy Banks v Goodfellow for the purpose of making a simple will disposing of modest assets to obvious beneficiaries.

Frequently Asked Questions

What are the four limbs of the Banks v Goodfellow test?

Cockburn CJ stated in Banks v Goodfellow [1870] LR 5 QB 549 that a testator must: (1) understand the nature of making a will and its effects — knowing that the document disposes of property on death; (2) understand the extent of the property being disposed of — not necessarily knowing its precise value, but having a general understanding of what they own; (3) understand the claims of those who might expect to benefit — knowing who has a natural claim on their bounty (typically close family) even if they choose to exclude them; (4) suffer from no 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. All four limbs must be satisfied at the time the will is made.

Does having dementia mean I cannot make a valid will?

Not automatically. A person with dementia may still have testamentary capacity if, at the time of giving instructions and executing the will, they satisfy the Banks v Goodfellow test. The condition must not be so advanced as to destroy any of the four limbs. Crucially, capacity is assessed at a specific point in time — a person with fluctuating capacity may have a 'lucid interval' during which a valid will can be made. The burden of proof is on those challenging the will to show lack of capacity, though where there are suspicious circumstances the burden may shift to those propounding the will. Medical evidence from a treating clinician is often critical in these disputes.

What is the 'golden rule' in will making?

The 'golden rule' — articulated in Kenward v Adams [1975] and reinforced in Re Simpson [1977] — states that when a solicitor is instructed by an elderly or seriously ill testator, the solicitor should arrange for a medical practitioner to assess the testator's capacity and record that assessment before the will is executed. The doctor should ideally be present at execution and should sign a certificate of capacity. The purpose is to provide contemporaneous evidence that will be available if the will is later challenged. Failure to follow the golden rule does not invalidate the will but significantly increases the risk of a successful capacity challenge.

What is a 'lucid interval' in the context of will making?

A lucid interval is a period during which a person whose mental faculties are generally impaired nonetheless has sufficient clarity of mind to satisfy the Banks v Goodfellow test. English law has long recognised that a will executed during a lucid interval is valid even if the testator lacked capacity at other times. The lucid interval must be genuine and complete — not merely a period of reduced agitation or improved mood. Evidence of a lucid interval typically requires contemporaneous medical records, witness testimony about the testator's behaviour at the time of execution, and often expert psychiatric evidence.

How does Banks v Goodfellow differ from the Mental Capacity Act 2005?

The Banks v Goodfellow test and the Mental Capacity Act 2005 are different tests for different purposes. The MCA 2005 establishes a functional test for decision-making capacity in general — used for decisions about medical treatment, finances, and welfare. It asks whether a person can understand, retain, weigh, and communicate information relevant to a decision. The Banks v Goodfellow test is the legal standard specifically for testamentary capacity and is more tailored to the act of making a will. A person who lacks capacity under the MCA 2005 for most purposes may still have testamentary capacity under Banks v Goodfellow; conversely, a person who passes MCA assessment might theoretically lack testamentary capacity if a specific delusion affects their will. The two tests coexist and courts apply each in its proper context.

How can a will be challenged on capacity grounds?

A will can be challenged by issuing a claim in the Chancery Division or Family Division of the High Court (or the county court for lower-value estates) for a declaration that the will is invalid. The claimant must plead that the testator lacked capacity under the Banks v Goodfellow test at the relevant time. Evidence typically includes: the testator's medical records in the period around execution; attendance notes from the will-drafting solicitor; witness statements from those present at execution; expert psychiatric evidence; and any earlier or later wills showing changed testamentary intentions. If the court finds lack of capacity, the purported will is void and the estate devolves under the prior valid will or, if none, under the intestacy rules. Costs in such proceedings are typically paid from the estate if the dispute was reasonable, but can fall on a losing party if the challenge was speculative.

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This article is for general information only and does not constitute legal advice. If you are advising on a will involving a testator with potential capacity issues, or if you are considering challenging a will on capacity grounds, consult a specialist contentious probate solicitor.