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Burden of Proof

Also known as: Onus of Proof, Evidential Burden

Definition

Burden of proof is the legal obligation to provide sufficient evidence to establish a claim in a will dispute, typically requiring proof on the balance of probabilities (more likely than not).

Understanding who bears the burden of proof determines who must gather evidence, what type of evidence is needed, and how strong that evidence must be to succeed in challenging or defending a will.

What Does Burden of Proof Mean?

In UK will disputes, burden of proof refers to the legal burden (ultimate responsibility to prove a claim) and the evidential burden (responsibility to present evidence raising an issue). The standard is balance of probabilities—the court must be satisfied something is more likely than not, essentially a 51% likelihood. This contrasts with criminal cases requiring proof beyond reasonable doubt. Though serious allegations like fraud or undue influence need stronger evidence, they still use the civil standard.

The burden framework varies by challenge type. For testamentary capacity, Key v Key [2010] established a three-stage process. First, a validly executed will that appears rational creates a presumption of capacity. Second, the challenger must raise "real doubt" with evidence such as medical records or witness testimony. Third, if real doubt exists, the burden shifts to the will's defenders to prove capacity at signing. For undue influence, no presumption exists—the burden stays with the challenger throughout, and Edwards v Edwards [2007] requires evidence "inconsistent with any other hypothesis." For knowledge and approval challenges, suspicious circumstances shift the burden to the propounder to prove the testator understood the will's contents.

Practical implications are substantial. Medical records, witness statements, expert opinions, contemporaneous solicitor notes, and previous wills may help meet the burden. The losing party typically pays both legal costs, which can reach tens of thousands of pounds. Understanding burden of proof is crucial for gathering the right evidence before probate, assessing realistic success prospects, and deciding whether to settle or proceed.

Common Questions

"Who has to prove a will is invalid in UK law?" The challenger must first raise 'real doubt' by providing evidence of issues like lack of capacity or suspicious circumstances. Once real doubt is established, the burden shifts to the will's defenders to prove validity on the balance of probabilities.

"What does 'balance of probabilities' mean in will disputes?" Balance of probabilities requires the court to decide which side's case is more likely true—essentially a 51% likelihood. This is lower than the criminal standard of 'beyond reasonable doubt,' though serious allegations like fraud require stronger evidence.

"Is the burden of proof different for different types of will challenges?" Yes. For testamentary capacity, there's an initial presumption of validity that shifts once doubt is raised. For undue influence, the challenger must prove it throughout. For knowledge and approval, suspicious circumstances shift the burden to the will's defenders.

Common Misconceptions

Myth: "If I can show any problem with a will, the court will invalidate it"

Reality: Simply raising concerns isn't enough. You must provide evidence creating "real doubt"—medical records, expert opinions, witness statements, or documentary evidence. Vague suspicions or family disagreements don't meet this threshold.

Myth: "The person defending the will has to prove it's valid from the start"

Reality: A properly executed will is presumed valid initially. The burden only shifts after challengers raise real doubt. For undue influence claims, the burden never shifts—challengers must prove it throughout.

  • Will Challenge: Burden of proof governs who must prove what at each stage of the dispute process.
  • Testamentary Capacity: The shifting burden framework applies most commonly in capacity challenges under Key v Key.
  • Undue Influence: Unlike capacity claims, the challenger bears the burden throughout with no presumption.
  • Suspicious Circumstances: These trigger burden shifting in knowledge and approval challenges.
  • Evidence: The evidence type and quality required depends on the burden of proof standard.

Need Help with Your Will?

Understanding burden of proof helps whether you're creating a will or considering a challenge. Knowing who must prove what supports informed decisions about evidence and strategy.

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Legal Disclaimer:

This article provides general information only and does not constitute legal or financial advice. WUHLD is not a law firm and does not provide legal advice. Laws and guidance change and their application depends on your circumstances. For advice about your situation, consult a qualified solicitor or regulated professional. Unless stated otherwise, information relates to England and Wales.