Last Updated on April 29, 2026 by tanya

Challenging a Will on Undue Influence or Lack of Capacity

 

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

 

Grounds to Contest a Will

When a loved one dies, disputes over their estate often arise and challenging a will on undue influence or lack of capacity are two of the most common grounds. This falls under contentious probate which is when people contest the validity of a will. Undue influence is where someone coerced the testator, and lack of capacity is where the testator did not understand the will. Evidence such as medical records, witness statements, and expert reports strengthens your case.

 

What Does Challenging a Will Mean?

Challenging a will means asking a court to declare it invalid. For a will to stand, it must follow the Wills Act 1837 and meet strict legal standards. If you prove that the will was signed under pressure or without mental capacity, the court can set it aside.

When that happens, the estate passes under either a previous valid will or the rules of intestacy.

 

Grounds to Contest a Will

The main reasons people contest wills may include:

 

• Lack of testamentary capacity
• Undue influence
• Lack of knowledge and approval
• Failure to meet formal requirements
• Fraud or forgery

 

What Does Lack of Capacity Mean?

Under the test for capacity, a person must:

 

Understand they are making a will and what it means.

Know the extent of their property.

Recognise the claims of people who might reasonably expect to benefit.

Make decisions free from mental illness or disorder that distorts their judgment.

 

If a testator cannot meet these requirements, their will lacks validity.

 

Example: If someone with advanced dementia signs a new will cutting out close family, you could challenge it for lack of capacity.

 

Undue Influence in Probate

Undue influence happens when someone forces or manipulates a testator to make a will against their true wishes

Example: A carer isolates an elderly person and pressures them into leaving everything to them. If you prove this, the court can strike down the will.

 

Who Has the Burden of Proof in Will Challenges?

The burden of proof is crucial in contentious probate:

 

• For lack of capacity, the law presumes a properly signed will is valid. If you show evidence of doubt, such as medical reports — the person defending the will must prove capacity.
• For undue influence, the challenger must prove coercion on the balance of probabilities. Because direct proof is rare, these cases are harder to win.

 

Evidence That Helps in Will Disputes

Strong evidence can make or break a probate challenge. Courts often rely on:

 

• Medical records showing cognitive decline or mental illness.
• Witness statements from carers, friends, or the drafting solicitor.
• Circumstantial evidence, such as sudden, unexplained changes in the will.
• Expert testimony from doctors or handwriting experts.

 

In undue influence claims, judges usually assess the overall picture rather than relying on direct proof.

 

Why You Need a Probate Solicitor

Contentious probate claims involve complex legal and evidential issues. Therefore a solicitor can:

 

• Analyse medical and legal records.
• Assess your prospects of success.
• Try to resolve disputes through mediation.
• Represent you in court if negotiation fails.

 

Most claims settle before trial, saving families stress, time, and cost.

 

Time Limits in Probate Challenges

You must act quickly:

 

• Inheritance Act 1975 claims (for financial provision) usually must be made within six months of the grant of probate.
• Claims based on capacity or undue influence have no strict time limit but should be issued as soon as possible. Delays weaken evidence and increase costs.

 

How to Prevent Will Challenges

If you want to protect your own will from disputes, check the following points:

 

• Get a medical capacity assessment when drafting your will.
• Use an experienced solicitor to oversee the process.
• Record your reasons for excluding family members.
• Communicate openly with beneficiaries.

 

These steps create a strong paper trail against future challenges.

 

Why Probate Disputes Keep Rising

Probate disputes are increasing because of:

 

• An ageing population and higher dementia rates.
• Blended families and complex family structures.
• Rising estate values, especially in London and the South East.
• Greater public awareness of inheritance rights.

 

 

FAQs About Challenging a Will

 

Can I contest a will after probate has been granted?

Yes, you can contest a will even after probate has been granted. However, it is harder once the estate has already been distributed. Acting quickly improves your chances of success, as courts prefer claims to be raised as soon as possible.

 

How hard is it to prove undue influence in a will dispute?

Proving undue influence is difficult because direct evidence is rare. Courts usually look at the wider circumstances, such as sudden changes in the will, dependency on a beneficiary, or isolation from family members. A strong case will include medical evidence, witness statements, and solicitor testimony.

 

What happens if a will is declared invalid?

If a court declares a will invalid, the estate is distributed according to the most recent valid will. If no earlier valid will exists, the estate passes under intestacy rules. This can drastically change who inherits.

 

How much does it cost to contest a will?

The cost of contesting a will depends on the complexity of the case and whether it settles out of court. Simple disputes resolved through negotiation may cost a few thousand pounds, while full litigation can reach tens of thousands.

We offer a range of fee structures, including ‘No Win, No Fee’ for certain cases along with other flexible funding – speak to our team to find out more.

 

Key Takeaways

• You can challenge a will for lack of testamentary capacity or undue influence.
• Undue influence means coercion that removes free will, not simple persuasion.
• Medical records, witness statements, and expert evidence strengthen claims.
• Early legal advice is critical due to strict deadlines and high costs.

 

We Can Help – Contact Us Today

Challenging a will can be emotionally draining during this difficult time. However, acting quickly, gathering the right evidence, and working with an experienced probate solicitor can make all the difference.

📞 Call us now on 0333 358 2345 📧 Or contact us online and we’ll call you back at a time that suits you.