Last Updated on April 28, 2026 by tanya

Burden of Proof in Inheritance Disputes Explained

 

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

 

Q&As Proving Your Case When Disputing a Will

The burden of proof in inheritance disputes decides which party must provide evidence to support their claim. Generally, the challenger carries this responsibility – whether alleging lack of mental capacity, undue influence, fraud, or forgery. However, in some cases, such as forgery or suspicious circumstances, the burden can shift back to the person seeking to uphold the will. However, claims under the Inheritance Act 1975 always place the burden on the claimant to prove lack of reasonable financial provision.

 

What Does “Burden of Proof”  Actually Mean in Inheritance Disputes?

The burden of proof puts responsibility on proving or disproving a claim by either the challenger or on the person defending the will. It includes:

• Evidential burden, which compels a party to initially bring forward enough evidence to support or defend a claim.
• Persuasive burden, which requires proving the claim to the court’s satisfaction – typically on the balance of probabilities. This means a fact is considered proven if it is more likely than noy to be true (greater than 50%).

 

Who Bears the Burden When a Will Is Challenged?

If someone challenges a will, the burden typically falls on the challenger to prove it. They may cite:

 

 Lack of mental capacity

Undue influence

Fraud, forgery

Lack of knowledge and approval

 

The court starts with a presumption that a duly executed Will is valid. So, challengers must provide evidence to overturn that presumption.

 

Mental Capacity: Who Must Prove What?

When dispute arises over a testator’s capacity:

 

• The challenger must first establish evidence that the testator lacked capacity (e.g., due to dementia or brain injury).
• If they do, the burden shifts to the will’s proponent to prove the person did have capacity

 

Once contested, medical records and expert reports become critical

 

Undue Influence: A High Bar for Challengers

Challengers must prove that someone exerted coercion so strong that it overruled or overwhelmed the testator’s own judgment. Courts require compelling evidence – and the standard for this is high

Circumstantial signs such as isolation, blocking contact with family, or suspicious behaviour may help. But these alone rarely clinch a case

 

Forgery & Reversal of the Burden of Proof

Typically, challengers bear the burden. However, in forgery claims, the court can shift the burden back to the person trying to prove the will is valid.

 

Lack of Knowledge and Approval: When Presumptions Don’t Work

By default, a properly executed will carries an assumption that the testator knew and approved its contents. But this presumption may fail under suspicion, for example:

 

• The testator was illiterate, visually impaired, or the will was drafted by a beneficiary.
• In such cases, the proponent must show the testator understood and approved the document

 

Contesting Under the Inheritance Act 1975

If someone claims the deceased failed to make reasonable financial provision (even if the Will is valid), the claimant must prove that claim. The burden lies firmly with them

They must present:

• Full financial disclosure at an early stage—current and future income, debts, assets
• Evidence of the deceased’s obligations, the size of the estate, disabilities, conduct, and other relevant factors

Failing to disclose fully may even lead the court to assume the claimant lacks financial need.

 

Why This Matters: Rising Number of Inheritance Disputes

Inheritance disputes in England and Wales have increased and contributing factors include:

 

• The passing of the asset-rich baby boom generation.
• Blended families, stepchildren, second marriages, and disinheritance.
• More dementia-related capacity challenges.
• COVID-era remote Will execution raising doubts.
• Increased public awareness—thanks to media exposure.

 

These disputes often impose high emotional and financial costs

 

Q&As on Proving Your Case in Inheritance Disputes

Q: What is the burden of proof in inheritance disputes UK?

A: The burden of proof depends on the issue: challengers usually must prove undue influence, lack of capacity, or forgery. In forgery cases, the burden can shift to the proponent. Under the Inheritance Act 1975, claimants must prove lack of reasonable financial provision with full disclosure.

 

Q: Who must prove mental capacity in a will dispute?

A: Initially, the challenger must show lack of capacity; if they succeed, the burden shifts to the Will’s proponent to prove the testator had capacity.

 

Q: Can the burden of proof ever shift in an inheritance case?

A: Yes. In fraud or forgery disputes (e.g. Face v Cunningham), the burden can shift to the proponent to prove the Will is valid.

 

Q: What evidence is needed for an Inheritance Act claim?

A: Full financial disclosure, plus proof of financial need, estate size, obligations, disabilities, conduct, and other relevant circumstances.

 

Practical Tips for Claimants and Executors

• Claimants: Gather medical evidence, financial records, and expert opinions early. Be thorough: incomplete disclosure can hurt your case.
• Executors or Beneficiaries: Keep clear records of execution, approval, medical assessments, and solicitor involvement to defend capacity or undue influence claims.
• Both Parties: Consider early mediation to avoid high costs and emotional toll, which often accompany court battles.

 

Call Us Today

If you are contesting a will on grounds of capacity, undue influence, or financial provision, understanding what the burden of proof is and gathering clear evidence can help you build a strong case. Working with an experienced probate solicitor can make all the difference during this emotional time.

We partner with law firms which 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.

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