Defamation Burden of Proof UK: Who Must Prove What in a Claim?

Understanding who must prove what in a UK defamation claim is essential before embarking on litigation. The burden of proof in defamation is more complex than in many other civil claims — it shifts between the parties depending on which defences are raised, and failing to understand this dynamic can fatally undermine an otherwise strong case.

The Claimant's Initial Burden

In English defamation law, the claimant bears the initial burden of establishing the elements of the claim. Under the Defamation Act 2013, the claimant must prove three things:

1. Publication: That the defendant published the statement — communicated it to at least one person other than the claimant.
2. Reference: That the statement refers to the claimant — either by name, or in terms that a reasonable reader would understand to identify them.
3. Serious harm: That the statement has caused, or is likely to cause, serious harm to the claimant's reputation.

These three elements together constitute the claimant's "prima facie case". Only once the claimant establishes them does the burden shift to consider the defendant's position.

The Serious Harm Threshold

Section 1 of the Defamation Act 2013 introduced the serious harm test, fundamentally altering the burden of proof in English defamation proceedings. Before 2013, a defamatory statement was presumed to cause damage to reputation — the claimant did not need to prove actual harm.

The Supreme Court in Lachaux v Independent Print Ltd [2019] UKSC 27 confirmed that serious harm must be demonstrated through evidence of actual or likely consequences, not merely inferred from the nature of the words. Claimants must gather evidence — of readership, of reactions from those who read the statement, of professional or social consequences — to discharge this burden.

For companies, section 1(2) imposes an additional burden: the statement must have caused, or be likely to cause, serious financial loss — not merely reputational damage. This is a significantly higher threshold that requires evidence of lost business, cancelled contracts, or quantifiable commercial harm.

How the Burden Shifts to the Defendant

Once the claimant establishes the prima facie case, the burden of establishing a defence shifts to the defendant. The principal statutory defences under the 2013 Act are:

• Truth (s.2): The defendant must prove, on the balance of probabilities, that the statement is substantially true. The burden of proving truth lies entirely with the defendant — the claimant does not need to prove the statement is false.
• Honest opinion (s.3): The defendant must show the statement was an expression of opinion rather than fact, was based on facts that existed at the time of publication, and that an honest person could have held that opinion on those facts.
• Public interest (s.4): The defendant must prove the statement concerned a matter of public interest, and that they reasonably believed publishing it served the public interest.
• Qualified privilege (s.15 and common law): The defendant must establish the privileged occasion. The burden then shifts back to the claimant to defeat privilege by proving malice.

The Truth Defence and the Reversal of the Presumption

The treatment of the truth defence is one of the most important aspects of the burden of proof in defamation. Under the old common law, there was a presumption that a defamatory statement was false — the defendant had to prove truth. This presumption survives under the 2013 Act: section 2 requires the defendant to prove truth.

This reversal of the usual civil burden — where the party making an allegation must prove it — reflects the policy decision that the law should protect reputation by requiring defendants to justify what they have said. It means that even where a defendant genuinely believes a statement is true, they must be able to prove it in court to avoid liability.

Standard of Proof in Defamation

Defamation claims are civil proceedings, so the standard of proof is the civil standard: the balance of probabilities (more likely than not, or "51%"). This applies to all elements — the claimant must prove the elements of the claim more likely than not, and the defendant must prove any defence more likely than not.

This is lower than the criminal standard of beyond reasonable doubt, but courts will apply closer scrutiny where allegations are serious. In Re B (Children) [2008] UKHL 35, the House of Lords confirmed that while the standard of proof does not change, the evidence required to meet it will be greater where the facts alleged are more improbable or serious.

Proving Serious Harm: What Evidence Is Needed?

The practical challenge for many claimants is assembling sufficient evidence of serious harm at an early stage. Useful evidence includes:

• Evidence of the number of people who read or viewed the statement
• Witness evidence from individuals who changed their opinion of the claimant after reading it
• Evidence of professional, commercial, or social consequences
• Documentary evidence of lost business, cancelled invitations, or withdrawn opportunities
• Evidence of the gravity of the allegation and the standing of the claimant in the relevant community

Courts take a realistic approach: minor hurt feelings or speculation about possible future damage will not suffice. Claimants need concrete evidence, gathered promptly after the publication comes to light.

Malice and the Burden of Proof

Where a defendant relies on qualified privilege — for example, for a statement made in a reference, a complaint to a regulator, or a report to the police — the defence will only succeed if the defendant acted in good faith. The burden of proving malice (which defeats the privilege) lies with the claimant.

Malice is defined as either knowledge that the statement was false, reckless indifference to its truth, or a dominant improper purpose. Proving malice is challenging because it requires evidence of the defendant's state of mind at the time of publication. Internal documents, emails, and communications showing the defendant knew the statement was false are often the most direct evidence available.

Practical Implications for Claimants

The burden of proof framework in defamation has several important practical implications:

• Gather evidence immediately: Screenshots, web archive captures, and witness statements should be collected as soon as a defamatory publication comes to light, before content is deleted or memories fade.
• Document consequences: Keep records of any professional, commercial, or social harm — cancelled meetings, lost clients, withdrawn job offers, or changed relationships — to support the serious harm case.
• Understand the defendant's likely defences: The strength of any truth or honest opinion defence should be assessed at the outset to evaluate whether a claim is viable.
• Act promptly: The one-year limitation period and the practical difficulties of gathering fresh evidence both argue for early legal advice.

Conclusion

The burden of proof in UK defamation claims is a nuanced framework that requires claimants to establish publication, reference, and serious harm — while defendants must prove the elements of any defence they raise. Understanding this burden before commencing proceedings is essential to assessing the strength of a case and the evidence needed to succeed. Contact our defamation solicitors for advice on whether the evidence in your case is sufficient to meet the required standard.