Banks v Goodfellow and Testamentary Capacity

What Is Testamentary Capacity?

Testamentary capacity is a legal term for a person’s ability to make a valid will. It is not about intelligence, general memory, or even a formal diagnosis. Instead, it is about whether someone understood enough about what they were doing — at the time they made the will — to make that specific legal decision.

The Banks v Goodfellow Test: The Four Requirements

To have testamentary capacity under Banks v Goodfellow, a person making a will must have been able to demonstrate all four of the following at the time the will was made:

1. They understood what a will is and what making one means

The person must have appreciated that they were creating a legal document that would determine what happens to their possessions after their death. This does not require legal training — just a basic grasp of the nature and effect of a will.

2. They had a general awareness of what they owned

The person does not need to recall the precise value of every asset. What matters is that they had a broad understanding of the nature and approximate extent of their estate — their property, savings, possessions, and any significant financial interests.

3. They understood who might reasonably expect to benefit

The person must have been able to identify who might have a reasonable expectation of being included in the will — typically close family members or dependants. Importantly, they are entitled to exclude such individuals from their will, but they must have been aware of them and their potential claim.

4. They were not suffering from a delusion that affected the will

If a person had a false, fixed belief (a delusion) arising from mental illness, that belief must not have influenced the decisions made in the will. Mental illness alone does not invalidate a will. What matters is whether the illness distorted the testamentary decisions.

Why Is This Victorian Test Still Used?

Banks v Goodfellow has endured because it was designed specifically for will-making. It reflects the personal and relational nature of testamentary decisions — decisions that are often shaped by family history, values, and individual judgment, not just the ability to process information.

From a clinical perspective, the test maps well onto the cognitive and psychiatric factors most relevant to will-making: episodic memory (recalling beneficiaries and assets), abstract reasoning, insight, and the potential influence of psychiatric symptoms such as depression, psychosis, or delirium.

Crucially, the test sets a functional threshold rather than a diagnostic one. People with mild cognitive decline or early-stage dementia may still meet the criteria, provided their understanding of the relevant matters is sufficiently intact.

How Is the Mental Capacity Act 2005 Different?

The Mental Capacity Act 2005 (MCA) introduced a statutory framework that applies to a wide range of decisions — including financial affairs, healthcare, and decisions authorised by the Court of Protection. Under the MCA, a person lacks capacity if, because of an impairment or disturbance in the functioning of the mind or brain, they are unable to:

• Understand the relevant information
• Retain that information
• Use or weigh it as part of the decision-making process
• Communicate their decision

The MCA applies when courts consider statutory wills — wills made on behalf of someone who lacks capacity — but Banks v Goodfellow governs capacity to make a will personally. This means the law currently uses two different tests depending on the context.

Comparing the Two Tests

Could the Law Change?

The Law Commission’s review, Modernising Wills Law, has proposed replacing Banks v Goodfellow with a single statutory test based on the Mental Capacity Act framework. The aim is to create greater consistency and legal clarity across different types of capacity decisions.

However, this proposal is not without clinical complexity. The MCA’s functional model — particularly the requirement to ‘use or weigh’ information — may impose a more demanding standard than Banks v Goodfellow in some cases. Testamentary decisions often involve emotional and relational reasoning that does not map neatly onto structured functional tests.

For clinicians, any reform would likely affect how assessments are structured, documented, and challenged in court.

What Makes a Good Testamentary Capacity Assessment?

Whatever legal test applies, thorough and well-documented assessments share the same core qualities. A high-quality assessment should:

• Be decision-specific — focused on the individual’s understanding of this particular will
• Explore understanding of the will’s purpose, the estate, and the relevant beneficiaries
• Consider the potential influence of any diagnosed or suspected cognitive or psychiatric condition
• Use cognitive screening tools to inform — but not replace — clinical judgment
• Be documented clearly, setting out the legal framework applied, the clinical findings, and the reasoning behind the conclusions

Where there is cognitive impairment, fluctuating cognition, psychiatric history, or a significant risk of dispute, a contemporaneous written assessment becomes especially important. Given how frequently these assessments are reviewed retrospectively — sometimes years after the will was made — precision and clarity are critical.

In Summary

Banks v Goodfellow remains the governing legal test for testamentary capacity in England and Wales. It is a focused, decision-specific standard that accommodates varying degrees of cognitive impairment while protecting against the influence of delusion and serious psychiatric disturbance.

The Mental Capacity Act 2005 provides a different but related framework, currently applied in the context of statutory wills and Court of Protection proceedings. Proposed legal reforms may eventually align these two standards.

For clinicians involved in medico-legal work, understanding the distinction between these frameworks — and keeping abreast of potential changes — is an essential part of practice. Testamentary capacity assessments carry significant personal, legal, and financial consequences. The goal of every assessment is to replace uncertainty with defensible, well-reasoned clarity.

Further Reading and Key References

The following sources are recommended for clinicians, legal professionals, and others seeking a deeper understanding of testamentary capacity, the Mental Capacity Act, and current reform proposals.

Legal Authorities and Legislation

• Banks v Goodfellow (1870) LR 5 QB 549 — the foundational judgment establishing the four-limb test for testamentary capacity in England and Wales.
• Mental Capacity Act 2005 (c.9) — the statutory framework governing decision-making capacity across a broad range of health, financial, and legal decisions. Available at: legislation.gov.uk
• Mental Capacity Act 2005: Code of Practice (2007), Department for Constitutional Affairs — the statutory guidance accompanying the Act, setting out how the principles should be applied in practice.
• Re Key [2010] EWHC 408 (Ch) — an important case confirming that the Banks v Goodfellow test governs testamentary capacity, and clarifying the approach to suspicious circumstances and want of knowledge and approval.
• Simon v Byford [2014] EWCA Civ 280 — Court of Appeal guidance on the standard of proof in testamentary capacity cases and the approach to conflicting medical evidence.
• Walker v Badmin [2014] EWHC 71 (Ch) — a case applying both Banks v Goodfellow and Mental Capacity Act principles, relevant to the relationship between the two frameworks.

Law Commission and Reform

• Law Commission, Modernising Wills Law (Law Com No 416, 2025) — the Law Commission’s final report proposing reform of the law of wills, including the proposal to replace Banks v Goodfellow with a statutory test modelled on the Mental Capacity Act. Available at: lawcom.gov.uk
• Law Commission, Making a Will (Consultation Paper No 231, 2017) — the earlier consultation paper setting out the issues with existing law and options for reform, including detailed analysis of testamentary capacity.

Clinical and Medico-Legal Guidance

• British Medical Association and The Law Society, Assessment of Mental Capacity: A Practical Guide for Doctors and Lawyers (4th ed, 2015) — an authoritative joint guidance document covering capacity assessment across multiple legal contexts, including will-making.
• Royal College of Psychiatrists, CR223: Capacity to Make a Will (2023) — clinical guidance from the Royal College of Psychiatrists on conducting testamentary capacity assessments, including documentation standards and the interface between clinical and legal frameworks.
• Jacoby R and Steer P, ‘How to Assess Capacity to Make a Will’ (2007) 335 BMJ 155 — a widely cited practical article for clinicians on the conduct of testamentary capacity assessments.
• Shulman KI, Cohen CA, Kirsh FC, Hull IM, Champine PR, ‘Assessment of testamentary capacity and vulnerability to undue influence’ (2007) 164 American Journal of Psychiatry 722 — an influential paper examining the clinical assessment of testamentary capacity and the related issue of undue influence.

Useful Online Resources

• Court of Protection: gov.uk/courts-tribunals/court-of-protection — information on the court’s role in authorising statutory wills and other decisions for those lacking capacity.
• Office of the Public Guardian: gov.uk/government/organisations/office-of-the-public-guardian — guidance on lasting powers of attorney and deputyship, relevant to understanding the broader capacity framework.
• Mental Capacity Law and Policy: mentalcapacitylawandpolicy.org — an academic resource exploring the intersection of mental health law, capacity, and the justice system.

Halcyon Doctors

Halcyon Doctors specialises in mental capacity assessments, including testamentary capacity, retrospective capacity opinions, and expert medico-legal reports. Our consultants are experienced in cognitive impairment and capacity law across a range of clinical and legal contexts.