Defamation Explained: Libel, Slander and the Serious Harm Threshold

Two words get used almost interchangeably to describe defamation in the UK: libel and slander. They are not quite the same thing, though the practical gap between them has narrowed a great deal. Before looking at defences or process, it is worth understanding what a claimant actually has to prove, what the "serious harm" threshold really means, and how sharply England and Wales, Scotland, and Northern Ireland diverge on that last question.

Libel vs Slander: Permanent Form vs Passing Words

The traditional common-law distinction is between libel, defamation in a permanent or recorded form, and slander, defamation in a transient form such as spoken words or gestures. Historically this mattered a great deal: slander generally required proof of actual financial loss (special damage) unless it fell into one of a handful of exceptions, while libel did not.

In practice, the distinction matters far less today than the label suggests. Almost everything published now exists in a stored, reproducible form: a social media post, a text message, a recorded video, a captioned image, and a broadcast are all treated as libel because they persist and can be re-read or re-watched, not because someone deliberately chose "the permanent kind" of defamation. Genuine slander cases, purely spoken exchanges with no recording, have become comparatively rare precisely because so much everyday communication now leaves a durable trace. None of this changes which statute or threshold applies; it simply affects how the underlying statement is classified.

What a Claimant Actually Has to Prove

Stripped of the labels, a defamation claimant generally has to establish three things:

1. Publication to a third party. A statement made only to the claimant themselves, with no one else seeing or hearing it, is not defamation. Defamation protects reputation in the eyes of others, so someone else has to have received the statement.
2. Reference to the claimant. The statement has to identify the claimant, whether by name, clear implication, or context that would let a reasonable reader or listener work out who was meant.
3. A defamatory meaning. The statement has to actually carry a meaning capable of harming the claimant's reputation, not merely be unflattering, embarrassing, or something the claimant dislikes.

Of these three, "meaning" is usually the issue that decides a case. Two people can read the same sentence and take away different impressions of what it accuses someone of, and English, Scottish, and Northern Irish courts have all developed a practice of trying to pin down the single, objective meaning a reasonable reader would take from a statement before going any further. A great deal of defamation litigation is, in substance, an argument about what a statement meant, not just whether it was true.

The Serious Harm Threshold

England and Wales and Scotland both add a further, statutory hurdle on top of the traditional test: the statement is not treated as legally defamatory at all unless it clears a serious harm bar.

Section 1 of the Defamation Act 2013 puts it plainly: "A statement is not defamatory unless its publication has caused or is likely to cause serious harm to the reputation of the claimant." Section 1(2) sets a stricter version of the same test for a body that trades for profit, requiring serious financial loss rather than general reputational harm.

This is not a rubber-stamp requirement. In Lachaux v Independent Print Ltd [2019] UKSC 27, the Supreme Court held that s.1 requires a claimant to prove that serious harm has actually occurred, or is likely to occur, based on the real facts and circumstances of the publication, not merely on the inherently defamatory character of the words themselves. A statement that would obviously harm most people's reputation "on its face" can still fail the s.1 test if the specific facts show it did not, or was not likely to, cause serious harm in that particular case, for example because it reached a tiny audience, was widely disbelieved, or was published to people who already knew the truth. Lachaux significantly raised the practical bar for bringing a claim in England and Wales, and Scotland's near-identical s.1 wording in the Defamation and Malicious Publication (Scotland) Act 2021 is generally read the same way.

The Three-Nation Split

This is the point where UK defamation law genuinely divides rather than just varying at the edges.

England and Wales

The Defamation Act 2013 came into force on 1 January 2014 and today applies to England and Wales only. (A small number of its provisions once extended to Scotland, but those were repealed for Scotland on 8 August 2022, when Scotland's own Act took over the field.) Its s.1 serious harm threshold, as interpreted in Lachaux, is the governing test for whether a statement is defamatory at all.

Scotland

The Defamation and Malicious Publication (Scotland) Act 2021 (asp 10) commenced on 8 August 2022. Its s.1 imposes the same serious harm threshold, including the equivalent serious financial loss test for profit-making non-natural persons, as a free-standing part of Scots law rather than an extension of the England and Wales Act.

Northern Ireland: Three Divergences, Not One

Northern Ireland is genuinely different, and in three specific ways, not just one. The Defamation Act (Northern Ireland) 2022 (nia/2022/30) received Royal Assent on 6 June 2022 and came into force the next day, 7 June 2022.

First, there is no serious harm threshold. Without a Northern Ireland equivalent of s.1, the older common-law test for what makes a statement defamatory continues to apply there, without the extra hurdle of proving actual or likely serious harm that Lachaux now requires in England and Wales.

Second, there is no single publication rule. England and Wales (s.8 of the 2013 Act) and Scotland both have a rule that treats republication of materially the same statement as part of the original publication for limitation purposes, so the limitation clock generally starts from the first publication. Northern Ireland has no equivalent provision, so the older multiple publication rule survives there. In practice, this means a fresh cause of action, and potentially a fresh limitation period, can arise each time the same defamatory material online is accessed or downloaded in Northern Ireland, rather than only once at first publication.

Third, there is no website-operator defence. England and Wales gives a website operator a defence against claims over a user's post if the operator cannot identify the poster but follows a notice-of-complaint procedure. Northern Ireland's 2022 Act has no equivalent section, so an operator sued over user-generated content accessible in Northern Ireland cannot rely on that route there.

These are not gaps waiting to be fixed by accident. Northern Ireland's Department of Finance reviewed this position in Summer 2024 and concluded it was "too soon to legislate further." That makes Northern Ireland's outlier status a considered, current policy choice rather than an unfinished piece of legislation, and it is worth taking seriously if a publication touches Northern Ireland, particularly anything published online that could be accessed there repeatedly over time.

Why This Matters in Practice

The upshot is that the same set of facts, the same statement, published in the same way, can be treated quite differently depending on which nation's law applies. A statement that would fail to clear the serious harm bar in England and Wales might still be actionable in Northern Ireland, where that bar does not exist. Online material that is time-barred in England and Wales under the single publication rule might still generate a live claim in Northern Ireland under the multiple publication rule. Working out which nation's law genuinely governs a publication, not just where the claimant happens to live, is one of the first practical questions in any real defamation matter.

For the statutory defences available once a statement clears the relevant threshold, see our guide to libel laws and defences. For the wider picture across all three nations, return to the UK defamation hub.

This page focuses on the concepts and on how the three UK jurisdictions compare. For a country-level overview of each system in its own right, see our separate guides to defamation law in the UK, Scotland and Northern Ireland.

This guide explains general concepts in UK defamation law and is not legal advice on any specific statement or dispute. Whether a particular statement is defamatory, and which nation's law applies, depends on detailed facts that a solicitor needs to assess directly.