Will Disputes & Capacity UK: Contesting a Will 2026

What this document is

Testamentary capacity is the mental threshold a person must meet at the moment they make a will for that will to stand up legally. The leading test still comes from an 1870 case, Banks v Goodfellow, which remains the yardstick courts apply in England and Wales despite the more recent Mental Capacity Act 2005.

In simple terms, the person making the will (the testator) must understand that they are making a will and what it does, have a general grasp of what they own, recognise the people who might reasonably expect to benefit, and not be suffering from any disorder of the mind that twists their sense of what is right. A will disputed on capacity grounds can be set aside entirely, which usually means an earlier valid will takes effect, or if none exists, the intestacy rules decide who inherits.

These disputes are fact-heavy, often turning on medical records, witness accounts, and the solicitor's file notes from the day the will was signed.

How to use this document

1. Gather the paperwork and the backstory. Pull together every version of the will you can find, any earlier drafts, and the contact details of the solicitor or will writer who prepared the final document. Note down when the testator's health started to decline, who was around them at the time, and anything that felt off about how the will came to be signed. A clear timeline is the backbone of any capacity challenge.
2. Request the will file and medical records. Under the Larke v Nugus principle, the solicitor who drafted the will can be asked to disclose their file, including attendance notes and any capacity assessment. You can also apply for the deceased's GP records and hospital notes, which often reveal dementia diagnoses, delirium episodes, or medication that clouded judgement around the date the will was signed.
3. Consider lodging a caveat at the Probate Registry. A caveat stops a grant of probate being issued while you investigate, giving you breathing room to build a case. Caveats last six months and can be renewed. This step matters because once probate is granted and the estate is distributed, unwinding it becomes far harder and more expensive.
4. Get a medical expert view on capacity. Courts place heavy weight on retrospective opinions from geriatric psychiatrists or other specialists who can review the records and comment on whether the testator likely met the Banks v Goodfellow test on the relevant date. Without this kind of evidence, a capacity claim is often little more than a hunch, and hunches do not win in court.
5. Try to resolve it before issuing a claim. Litigation over wills is expensive, slow, and corrosive to family relationships. Mediation, a round-table meeting, or a negotiated variation of the estate can often land a better outcome than a contested trial. If settlement fails, a claim in the Chancery Division is the formal route, but most capacity disputes settle long before a judge hears them.

Common questions