A will only counts if the person signing it knew and approved what was in it. That is a separate requirement from mental capacity, and it catches a different problem. Not whether someone was capable of making a will, but whether this particular document says what they actually wanted.
How is this different from capacity?
The two get argued together and confused all the time, so the difference is worth pinning down.
- Capacity is about the person. Were they mentally able to make a will at all?
- Knowledge and approval is about the document. Assuming they were capable, did they understand and accept what this will says?
Someone can have perfect capacity and still fail this test. Maybe the will was read to them too fast. Maybe it contained a clause they never asked for. Maybe they could not read the language it was written in, or they were blind or too weak to read it and nobody checked they had understood.
What does the court need to be satisfied of?
That the will says what the person signing it really wanted. The leading case is Gill v Woodall (2010), where the Court of Appeal set a will aside on this ground.
Older cases used a two-stage approach. First ask whether there were "suspicious circumstances", and only then require the will to be proved. Lord Neuberger said in Gill v Woodall that it is generally better to do it in one go. Look at all the evidence, and draw whatever conclusions you can from the whole picture. So the modern question is simply this: taking everything together, is the court satisfied the will said what the person wanted?
How strong is the presumption for a professionally drafted will?
Very strong. Gill v Woodall put it plainly. A will prepared by a solicitor, read over to the person making it, and then signed properly, carries a very strong presumption that it says what they intended.
That is the most useful practical point in this whole area, and it works both ways. If you are making a will, having it drafted or checked by a solicitor and read over to you is the best protection there is. If you are challenging one, you are pushing against that presumption, and you will need real evidence rather than a bad feeling.
The court did add a warning: the presumption should not be applied in a way that encourages challenges to wills or chips away at people's freedom to leave their money where they want.
What raises a real doubt?
- A beneficiary organised everything. Someone who does well out of the will booked the appointment, gave the instructions, and stayed in the room.
- No independent record of the instructions. The drafter cannot say what the will-maker actually told them, as opposed to what someone else said for them.
- The will was never read over or explained. Especially where the person had trouble with sight, hearing, reading or English.
- There is something in it nobody can explain. A clause that came from nowhere, or a change from a long-settled plan with no recorded reason.
- Speed. Instructions taken and the will signed within a very short window, particularly during serious illness.
How does this play out in practice?
Often it does not get far. In Woolfson v Woolfson (2026) a challenge that included want of knowledge and approval was struck out before trial, because the claim was not properly set out or supported. Serious allegations about how a will came to be made need detail and evidence, not just assertion. We went through that case in when a will challenge never gets off the ground.
What should you do about it?
If you are making a will, the safeguards are the same ones that protect against every other ground. Give your instructions yourself and on your own, have the document read over and explained to you, and make sure someone writes it down at the time. See protecting your will from a challenge.
If you think a will does not say what someone actually wanted, the will-drafting file is the document that matters. See how to challenge a will. This ground sits close to undue influence and fraudulent calumny, and the same facts often support more than one. The overview of legal challenges to wills compares them.
This article is for general information and is not legal advice. If you are worried that a will does not reflect what the person signing it understood or wanted, please get in touch for advice on your own situation.
Sources
Common questions
What is the difference between capacity and knowledge and approval?
Capacity is about the person: were they mentally able to make a will at all? Knowledge and approval is about the document: assuming they were capable, did they understand and accept what this particular will says? Someone with full capacity can still fail the knowledge and approval test if, say, the will was never read over to them, or it contains a clause they never asked for.
Does a solicitor-drafted will make a challenge harder?
Much harder. The Court of Appeal said so in Gill v Woodall. A will prepared by a solicitor, read over to the person making it, then properly signed, carries a very strong presumption that it says what they intended. A challenger has to push against that with real evidence.
Do courts still use the suspicious circumstances test?
The modern approach is to do it in one stage. In Gill v Woodall the Court of Appeal said it is generally better to look at all the evidence together and draw conclusions from the whole picture. The older approach asked first whether there were suspicious circumstances, and only then required the will to be proved. Suspicious circumstances still matter as evidence, but they are no longer a separate hurdle.
Oliver Asha
Solicitor · TEP · Founder of Make a Will
Oliver is a Solicitor (SRA number 372772) and a Trust and Estate Practitioner (TEP). He qualified in 2006 and he is founder at Make a Will, Make a Will Online, Digilegal Trustees and Capacity Vault. It is his mission to bring proper, solicitor-checked wills within reach of every family. He personally drafts and oversees the review of many of the guides on this site.
Verify Oliver’s credentials: Law Society · SRA register · STEP directory
Further Reading
- Stop a Probate Application - GOV.UK How to enter a caveat if you want to challenge a will
- Find a Solicitor - The Law Society Search for a solicitor who specialises in contentious probate
- Inheritance (Provision for Family and Dependants) Act 1975 - legislation.gov.uk The Act that lets family and dependants claim reasonable provision
- Wills Act 1837, section 9 - legislation.gov.uk The signing and witnessing rules a will must satisfy