On what grounds can I challenge the validity of a will?

On what grounds can I challenge the validity of a will? | Thursday 5 March 2026 | 4 min read

There are a number of possible arguments that you may be able to run to challenge the validity of a will. Each case will very much turn on its own unique set of facts but we set out below a summary of the possible challenges.

• The will has not been properly executed – For a will to be valid, it must comply with the provisions of the Wills Act 1837. This means that the will must:
•  Be in writing;
•  Be signed by the testator (i.e. the person making the will) or by another person on their behalf in their presence and at their direction;
•  Be signed (or the signature must be acknowledged) in the presence of two witnesses, who both need to be present at the same time; and
•  Be signed by each witness (or their signature must be acknowledged) in the presence of the testator (although the witnesses do not have to be in each other’s presence when they each sign or acknowledge their signature to the will).

You may also have concerns as to whether the signatures are genuine, which we can help you to investigate.

• The testator lacked mental capacity to make a will – A person will have capacity to make a will if:
•  They understood that they are making a will (meaning that they know that document will set out what will happen to their estate when they die);
•  They know what property and assets they own;
•  They know who the people are that they may consider leaving a gift too (such as their family members, even if they then decide to leave someone out); and
•  They are not suffering from any disorder of the mind or any delusion that would affect their understanding.

We can discuss with you whether any mental health conditions, dementia or an illness could have affected the testator’s testamentary capacity to make a valid will.

• The testator did not know and approve the content of their will – The testator must also know what the terms of the will say, and they must approve its content. This is usually done by the testator reading the will or having the will read to them before they sign it. There is a rebuttable presumption that a testator knows and approves the content of a will that has been properly executed.
• The testator was coerced or unduly influenced by somebody else to make the will – To successfully challenge a will on this basis, undue influence or duress must be a more probable reason why the will was made in such terms than any other hypothesis. Typically, you will need to evidence that the deceased would not have made a will in such terms unless they had been unduly influenced or coerced to do so. Red flags for possible undue influence include:
•  homemade wills prepared by someone who benefits substantially from the Estate
•  the inclusion of someone in a will for the first time
•  a significant change from previous wills where there is no obvious reason for such a change
•  a large increase in the proportion of an Estate being left to a person (particularly if the deceased was dependent on that person when the will was made)
•  the deceased was ill, frail or vulnerable when the will was made.

You might also be concerned that the testator’s view of you has been altered by someone telling untruths about you to the testator in order to poison their mind against you. We can explore this with you too.

• The testator married or entered into a civil partnership after the will was made – Marriage or entering into a civil partnership automatically revokes any will that was made before that date, unless the will is expressly stated to be made in contemplation of that marriage or civil partnership.

Challenging a will is a complex and emotional process. We can help and guide you through that process and advise you on strategies to resolve your claim without the need to go to court. Please click here to get in touch with Clare and Ashleigh.

Read our full wills and probate FAQs articles here.