Undue Influence in Will-Making: How Claims Work

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.

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.