Undue Influence in Will-Making: How Claims Work

How do I prove undue influence in a will challenge?

1In will cases, there is NO presumption of undue influence — unlike contract cases, the claimant must actively prove it was exercised
2Undue influence means the deceased's free will was overborne — the influence must amount to coercion, not merely persuasion or family pressure
3Suspicious circumstances (such as the beneficiary preparing the will or excluding existing family) can support an inference but are not conclusive
4Undue influence claims are among the hardest to prove — courts have found against claimants even in cases of clear manipulation that fell short of legal coercion
5Circumstantial evidence is key: isolation from family, dramatic change from previous wills, dependency on the beneficiary, and vulnerability of the testator

Undue influence in will cases must be actively proved — there is no presumption. The influence must have overridden the deceased's free will. Circumstantial evidence about isolation, dependency, and suspicious circumstances is key. These are the hardest will claims to succeed on.

Undue influence claims arise where a family member suspects that a parent, grandparent, or other relative was pressured or manipulated into making a will that benefited a particular person at the expense of others. The claim is that the will does not reflect the deceased's true wishes — it reflects the wishes of whoever exerted the influence.

This guide explains the legal test, the critical difference from contract undue influence, what evidence is needed, how courts assess these claims, and the practical challenges of bringing them.

The Legal Test for Undue Influence in Will Cases

The test for undue influence in the context of wills is strict. The influence exerted must have:

Amounted to coercion — not merely advice, persuasion, or emotional pressure that a person of ordinary firmness could have resisted
Overpowered the testator's free will and volition, so that the will was not the testator's own act but the act of the person exerting influence

The classic statement of the test comes from Hall v Hall (1868): “To be undue, the influence must be such as to take away the free agency of the testator.” Persuasion and appeals to the feelings and affections of a testator are not undue influence — even if effective. A testator who gives in to family pressure is still exercising their own choice.

No Presumption of Undue Influence in Will Cases

This is the critical difference from contract law. In contract cases, a presumption of undue influence arises where a relationship of trust and confidence is proved — and the burden shifts to the defendant to rebut it.

In will cases, there is NO presumption of undue influence, regardless of the relationship between the testator and the person alleged to have influenced them. An adult child who cares for an elderly parent, even in circumstances of significant dependency, is not presumed to have exercised undue influence over the parent's will.

This means the claimant must prove undue influence on the balance of probabilities — which is very difficult because the key witness (the testator) is dead.

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Suspicious Circumstances: What Can Be Used as Evidence

Because direct evidence of undue influence is rarely available, claims rely on circumstantial evidence and suspicious circumstances. Courts consider:

The beneficiary prepared the will or accompanied the testator to the solicitor and gave instructions
The testator was isolated from other family members by the beneficiary
The will makes a dramatic and unexplained departure from the testator's previously expressed intentions
The testator was in a vulnerable state — elderly, ill, mentally impaired, or financially dependent on the beneficiary
The testator changed their will multiple times, each time increasing provision for the beneficiary
Family members who expected to benefit were actively excluded or their contact with the testator was prevented
The beneficiary had control over the testator's finances or day-to-day life

Suspicious circumstances alone do not prove undue influence but they shift the evidential focus and increase the scrutiny applied by the court. They may also support a claim of lack of knowledge and approval (see our guide on the grounds for contesting a will).

Evidence Needed

Witness statements from family members, neighbours, and carers about the testator's relationship with the beneficiary and any observed coercive behaviour
Text messages, emails, and letters showing controlling or manipulative behaviour
Financial records showing control over the testator's money
Medical records showing vulnerability and dependency
Evidence of exclusion — call logs, visitor records showing the testator was prevented from seeing others
The solicitor's file showing who gave instructions, whether the testator was seen alone, and what attendance notes record

Practical Steps

Enter a caveat immediately — see how to enter a caveat
Consult a specialist contentious probate solicitor
Gather evidence promptly — witnesses' memories fade and documents may be lost
Consider whether a claim for lack of testamentary capacity or lack of knowledge and approval may be stronger — these are often pleaded alongside undue influence
Consider mediation — see mediation in estate disputes
Note the 6-month Inheritance Act deadline if you also have a financial provision claim — see Inheritance Act 1975 claims

For the full contentious probate picture, see our introduction to contentious probate, our guide on lack of testamentary capacity, our guide on time limits for contesting a will, and our guide on costs in contentious probate. For the non-contentious estate, see our estate administration checklist.

Get started with Farra for help with the administration side of the estate.