When a will is made, it’s about respecting a person’s choices at what is often a tender moment in their life. In England and Wales, the law requires the person signing a will to have “testamentary capacity“, which simply means they understand what they are doing and what it means. For families, that legal phrase can feel cold and technical at a time that is anything but. This guide explains in plain language how professionals check someone has capacity to make or change a will, what we look for, and why a careful, person-centred approach protects everyone involved.
Key Points
- Testamentary capacity is the legal test for whether someone can make or change a will, based on a case from 1870 that still applies today.
- Professionals check four things: does the person understand what a will does, know roughly what they own, recognise who might expect to benefit, and make decisions free from serious mental disorder.
- The Mental Capacity Act 2005 shapes how we assess capacity generally, reinforcing that capacity is decision-specific, time-specific, and must be assumed unless proved otherwise.
- Good assessments are calm, paced, and adapted to how the person communicates best, giving them every reasonable chance to understand and express their wishes.
- An independent, well-evidenced assessment can prevent later disputes, ease family tensions, and keep the person’s voice at the centre of any decision.
What Testamentary Capacity Actually Means
Testamentary capacity is the legal and mental ability someone needs to make or change a valid will. The test comes from a case called Banks v Goodfellow from 1870, and it is still the correct legal test today, separate from the Mental Capacity Act framework.
In simple terms, someone must understand what a will does, have a broad sense of what they own, and make decisions that are not driven by significant mental disorder or fixed delusions. Testamentary capacity is judged at the time instructions are given and when the will is signed, which is why timing and careful recording matter so much.
The Banks v Goodfellow Test Explained
Banks v Goodfellow sets out four specific things professionals check when assessing testamentary capacity. The person must:
Understand what making a will means. They need to grasp that the document distributes their property after death and is usually intended as their final instructions.
Have a general sense of what they own. Not every bank balance to the last pound, but a realistic understanding of the size and type of assets (for example, house, savings, pensions).
Be aware of who might reasonably expect to benefit. Typically close family or others who have a moral claim, so they can consciously choose to include or exclude them.
Be free from any disorder of the mind that distorts their decisions. Mental illness, dementia or delusions do not automatically remove capacity, but they must not be driving the choices in the will.
If these criteria are met, the person can make a will even if they are older, have a diagnosis, or make choices others see as unwise. Where there is doubt, the courts expect clear professional evidence showing how each part of the test has been considered.
How the Mental Capacity Act Fits In
Although Banks v Goodfellow is the main legal test for wills, the Mental Capacity Act 2005 shapes how I think about and assess capacity in everyday practice. The Act says capacity is decision-specific and time-specific, and that a person must be assumed to have capacity unless it is established that they lack it.
Under section 3 of the MCA, someone is treated as unable to make a decision if they cannot understand, retain, use or weigh relevant information, or communicate their decision, even with appropriate support. In testamentary cases, I apply these functional abilities within the Banks v Goodfellow framework, checking whether the person can use and weigh information about who might be affected by their will.
There is ongoing debate about aligning the common law test with the MCA definition, but at present Banks v Goodfellow remains the authority for wills. For families, the important point is that any assessment should be structured, respectful, and clearly linked to these recognised legal tests.
What I Look for in an Assessment
A good testamentary capacity assessment is not a tick-box exercise. It is a structured conversation built around the person’s life, wishes and understanding. When I assess testamentary capacity, I:
Prepare carefully. I review background information, existing wills, family circumstances and any diagnoses, so questions can be pitched at the right level and unnecessary stress is avoided.
Explain in plain English. I use everyday language, visual aids or repetition if needed, so the person has every realistic chance to understand what we are discussing.
Explore the four Banks v Goodfellow areas explicitly. I ask open questions about what a will does, what they own, who is important in their life, and why they wish to make particular gifts or changes.
Check for undue influence or pressure. I gently explore whether anyone is pushing, rushing, or coaching the person, especially where there are significant changes from a previous will.
Record the process in detail. I capture the person’s own words, their reasoning, and the support offered, so the report can stand up in court if the will is challenged later.
Professionals who follow the “golden rule” will often advise a formal capacity assessment where there is advanced age, serious illness, complex family dynamics or significant asset changes, to reduce the risk of future disputes.
A Compassionate, Independent Approach
Testamentary capacity assessments sit at the intersection of law, emotion and family history, which is why a calm, independent presence can make such a difference. In my practice, I focus on giving the person time, dignity and space to express themselves, while still applying the legal tests rigorously.
As an independent social worker, I am not tied to any firm, care provider or family faction, which helps everyone trust that the assessment is fair, evidence-based and centred on the person’s wishes. Families and solicitors often tell me that this reduces conflict, clarifies whether a will can safely proceed, and provides reassurance that, whatever happens later, there is a careful, compassionate record of what the person understood at the time.
If you are worried about whether someone has capacity to make or change their will, or if you need an independent assessment to support a legal process, get in touch for a chat. I am here to help guide you through what can feel like a daunting process with clarity and care.
Questions About Testamentary Capacity
Can someone with dementia still make a valid will?
Yes, dementia does not automatically mean someone lacks testamentary capacity. What matters is whether they understand what a will does, know roughly what they own, and can make decisions free from delusions at the time they give instructions and sign the will. Many people with early or moderate dementia retain capacity for this specific decision.
Who can assess whether someone has testamentary capacity?
Testamentary capacity is usually assessed by independent social workers, doctors, or psychiatrists with experience in mental capacity law. The assessor must understand both the Banks v Goodfellow test and the Mental Capacity Act 2005, and should have no connection to the family or the will’s beneficiaries. Solicitors may also form a view, but an independent professional assessment provides stronger evidence if the will is later challenged.
When is the best time to arrange a testamentary capacity assessment?
The best time is when instructions are given and again when the will is signed, especially if there is any concern about fluctuating capacity. If someone’s health is declining, it is better to arrange an assessment sooner rather than later. Early assessment protects the person’s wishes and reduces the risk of disputes after they die.
What happens if someone lacks capacity to make a will?
If someone lacks testamentary capacity, they cannot make or change a will themselves. In some cases, the Court of Protection can make a statutory will on their behalf, but this requires a formal application and evidence about what the person would have wanted. It is a complex process, which is why early planning with a Lasting Power of Attorney is so valuable.
Can family members challenge a will based on lack of capacity?
Yes, family members can challenge a will if they believe the person lacked testamentary capacity when it was made. This is why independent professional assessments are so important, they provide clear evidence of what the person understood at the time. A well-documented assessment often prevents costly legal disputes after someone has died.
How is testamentary capacity different from other types of capacity?
Testamentary capacity uses the Banks v Goodfellow test, which is specific to wills and slightly different from the Mental Capacity Act test used for other decisions. Someone might have capacity to make a will but lack capacity for more complex financial decisions, or vice versa. Capacity is always decision-specific and time-specific.
What should be included in a testamentary capacity assessment report?
A good report should explain how each of the four Banks v Goodfellow criteria was assessed, record the person’s own words and reasoning, and note any support given during the assessment. It should also address whether any mental disorder affected the decision, and whether there were signs of undue influence or pressure. The report must be clear, evidence-based, and suitable for legal scrutiny.
