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Dispute a Will Because of Dementia
Last Updated on April 22, 2026 by tanya
Dispute a Will Because of Dementia
About Our Legal Expert: This content is produced under the oversight of Michael Jefferies, First Personal Injury Director, who brings over 30 years of legal experience.
Written by Tanya Waterworth, Digital Content Writer
Your Complete Guide to Contesting Mental Capacity in a Will
Disputing a will because of dementia is never easy. In England and Wales, challenges to a will are increasing as more families question whether the document truly reflected the person’s wishes. If you suspect dementia played a role in the creation or signing of a will, here’s your guide to the legal grounds for challenging a will and the next steps for bringing a contentious probate claim.
So, if you want to challenge a will because you believe your loved one lacked mental incapacity, we can help.
We partner with specialist contentious probate lawyers who offer a No Win No Fee option, along with other flexible funding – contact our team today to arrange a free consultation.
Can You Dispute a Will Because of Dementia?
Yes. You can dispute a will if the person who made it (the “testator”) lacked testamentary capacity due to dementia. Under English and Welsh law, a will is only valid if the testator understood what they were doing when they created it. Dementia, Alzheimer’s disease and similar cognitive conditions can undermine that understanding, especially in the later stages.
However, the key question is:
Did the testator have testamentary capacity at the time they gave instructions and signed the will?
Capacity can fluctuate, and some people experience “lucid intervals”. This is why gathering evidence is crucial. If you can show the testator did not understand the nature of making a will, its effects, the extent of their estate, or who they should consider as beneficiaries, the will may be declared invalid.
Legal Grounds to Contest a Will Due to Dementia
When you dispute a will because of dementia, you generally rely on one or more of the following legal grounds. Each serves as a potential route to invalidate the will and replace it with an earlier valid version or apply intestacy rules.
1. Lack of Testamentary Capacity
This is the most common ground for disputing a will involving dementia. The testator should:
- Understand they are making a will and its consequences
- Know the nature and extent of their estate
- Understand who they should reasonably consider as beneficiaries
- Not be affected by a mental disorder that distorts their decisions
If dementia impaired the testator’s cognitive abilities, you may have a strong basis to argue they lacked capacity. This may include memory loss, confusion, impaired reasoning, or delusions
2. Lack of Knowledge and Approval
Even if the testator technically had capacity, a will can still be challenged if they did not fully understand or approve its contents. Dementia increases the risk that the person signing the will was not aware of key changes, did not fully understand the implications of the clauses, or did not read (or have read to them) the final document.
Suspicious circumstances, such as major, unexpected changes to beneficiaries, can strengthen this argument.
3. Undue Influence
People living with dementia are more vulnerable to manipulation. If someone exercised pressure, coercion, or control over the testator to obtain a benefit from the will, you may be able to challenge it on the basis of undue influence.
Undue influence is considered as difficult to prove, but evidence such as sudden changes to the will, isolation of the testator, or a beneficiary’s involvement in the will-making process can support your claim.
4. Fraud or Forgery
Dementia can create opportunities for others to exploit the testator. Fraud may include misrepresentation, deceit, or forging the will itself. If signatures appear inconsistent or if you have concerns about how the will was produced, forensic investigations can help in this regard.
5. Failure to Comply with Formal Legal Requirements
Even when dementia is involved, you can also rely on standard procedural grounds, such as:
- Improper witnessing
- Incorrect signing process
- Use of a template that does not meet the statutory requirements
These can invalidate the will regardless of capacity issues.
Key Evidence Required When Contesting a Will Because of Dementia
To build a strong contentious probate claim, you need evidence showing the testator lacked capacity or was otherwise unable to make a valid will. Useful evidence may include:
Medical Records
- GP notes
- Hospital assessments
- Memory clinic reports
- Psychiatric evaluations
These documents are vital as they help show the progression and severity of the dementia.
Witness Statements
Statements from carers, family members, friends, neighbours, or professionals can show patterns of confusion, forgetfulness, or impaired decision-making.
Earlier Wills
Comparing the disputed will to previous versions can help identify suspicious changes.
Next Steps: How to Make a Contentious Probate Claim
If you want to challenge a will in England and Wales because of dementia, here are your next steps:
Step 1: Seek Specialist Contentious Probate Advice Immediately
Probate disputes are complex and time-sensitive. Consulting a solicitor specialising in contentious probate or will disputes early ensures you receive expert guidance.
Time limits may apply, such as claims under the Inheritance (Provision for Family and Dependants) Act 1975, so taking action quickly is essential.
Step 2: Enter a Caveat to Pause the Probate Process
To stop the estate being distributed before your dispute is resolved, you can lodge a caveat at the Probate Registry. This prevents probate from being granted for six months, giving you time to gather evidence and build your case. It can be renewed.
Step 3: Gather Evidence and Build Your Claim
Your solicitor will help you collect key documents, obtain medical records, analyse will-writing notes, and identify witnesses. This stage is critical to demonstrating the testator’s cognitive state and the circumstances surrounding the will.
Step 4: Pre-Action Correspondence
Your solicitor will send a formal letter outlining your concerns and legal grounds for disputing the will. This initiates the legal process and opens the door to negotiation or mediation.
Step 5: Attempt Alternative Dispute Resolution (ADR)
Most contentious probate cases settle before reaching court. Mediation is often faster, less stressful, and more cost-effective than litigation. Courts encourage parties to attempt mediation (ADR) before proceeding to trial.
Step 6: Issue Court Proceedings (If Necessary)
If settlement is not possible, your solicitor will issue proceedings in the court to challenge the validity of the will. The court will review the evidence and decide whether the will stands or is set aside.
Don’t Hesitate – Get Started Today
Disputing a will because of dementia is a deeply emotional process. However, the law in England and Wales provides strong protections to ensure a will genuinely reflects the testator’s intentions. If dementia affected their ability to make sound decisions, you have the right to challenge the will and seek a fair outcome.
Our partner panel of law firms, who are highly experienced in contentious probate, can guide you through the process of making a claim with care and understanding.
Call us today at 0333 358 2345 or contact us online to arrange your free consultation.