What Evidence Do I Need for a Defamation Claim UK?

Before instructing a defamation solicitor, one of the most common questions clients ask is: what evidence do I actually need? The strength of your evidence determines whether your case is viable, whether a defendant is likely to settle, and ultimately, whether you will succeed at trial. This guide maps out the main categories of evidence — and what each one proves in the context of a UK defamation claim.

The Legal Framework: What Evidence Must Establish

Under the Defamation Act 2013, a successful defamation claim requires you to prove three things:

1. Publication: The statement was communicated to at least one person other than you.
2. Identification: The statement referred to you.
3. Serious harm: The statement has caused or is likely to cause serious harm to your reputation (or, for businesses, serious financial loss).

Your evidence must speak to each of these elements. A case that is strong on identification but weak on harm will struggle before a judge. Equally, a case where harm is obvious but publication cannot be proven creates procedural difficulties.

Evidence Category 1: Proof of Publication

You must be able to prove the statement was published — that it was communicated to one or more people beyond yourself. For online defamation, this typically means:

• Screenshots with metadata: Take full-page screenshots that include the URL, the date and timestamp, and the platform. Use a desktop browser where possible — mobile screenshots sometimes omit key data. Tools like web.archive.org can capture and preserve the content independently.
• View counts and engagement metrics: Evidence that a social media post received significant views, shares, likes, or comments helps establish the extent of publication. A post seen by 50,000 people has caused greater potential harm than one seen by five.
• Cached or archived copies: If content is deleted, Google Cache or the Wayback Machine may retain copies. Preserve these immediately — they can disappear.
• Witness statements: Statements from individuals who saw or read the defamatory content can be powerful, particularly if those witnesses can speak to their reaction and any change in their view of you.

For print or broadcast defamation, preserve the original publication, the broadcast recording, or a copy of any newspaper or magazine article.

Evidence Category 2: Identification

The statement must be shown to refer to you. In most cases this is straightforward — your name appears in the publication. But where the statement refers to you by description, implication, or nickname, you may need evidence to establish the "innuendo":

• Evidence that readers in a particular group or community would understand the reference to mean you.
• Witness statements from people who confirm they read the statement as referring to you.
• Context showing you are the only or primary person fitting the description.

Evidence Category 3: Establishing Serious Harm

This is the element most often underestimated. Courts require actual or likely serious harm — not just embarrassment, upset, or inconvenience. The evidence you can produce here often determines whether proceedings are viable at all.

Evidence of Reputational Harm

• Witness statements: From colleagues, clients, business contacts, or friends who confirm that the statement changed their view of you — ideally in specific terms ("I was about to refer a client to them but decided not to after reading that").
• Social media reactions: Screenshots of hostile comments, shares, or public attacks on your reputation following publication.
• Evidence of being ostracised: If you were excluded from social groups, professional networks, or events following publication, document this.

Financial Evidence of Harm

• Lost business records: Evidence of contracts not renewed, clients lost, projects cancelled, or partnership opportunities withdrawn — particularly where a causal link to the defamatory publication can be demonstrated.
• Income comparisons: Tax returns, invoices, or business accounts showing a downturn following the publication date.
• Employer communications: Emails or letters from employers that reference the defamatory content, or evidence of disciplinary action, suspension, or dismissal linked to it.

Medical Evidence of Distress

• GP records: A letter or records from your doctor noting a presentation with anxiety, depression, or other psychological symptoms in the period following publication.
• Psychiatric or psychological evidence: A report from a psychologist or psychiatrist is valuable in more serious cases, particularly where psychiatric injury is claimed as a head of damages.
• Note: distress alone does not establish serious harm, but it is relevant to the quantum of any damages award.

Evidence Category 4: Identifying the Defendant

You must know — or be able to identify — who published the statement. Where the publisher is known, this is straightforward. Where the statement was published anonymously, you may need to apply for a Norwich Pharmacal Order to compel the platform to disclose the identity of the poster. To obtain this, you will need sufficient evidence to establish a good arguable case for defamation.

In some cases, evidence about the identity of the publisher can be built from context — the language used, knowledge of private facts, or IP address information obtained through other means.

Evidence Category 5: Disproving Available Defences

A defendant may rely on the statutory defences of truth, honest opinion, or public interest. You should gather evidence that undermines any likely defence:

• Truth defence: Evidence that the statement is false — records, receipts, witness statements, professional records, or official documentation that contradicts the allegation.
• Honest opinion defence: Evidence that the statement presents itself as fact rather than opinion, or that the defendant did not genuinely hold the view expressed.
• Public interest defence: Evidence that the publication was not in the public interest, was irresponsible, or failed to meet responsible journalism standards.

How to Preserve Evidence Safely

Evidence can disappear quickly — defendants delete posts, platforms take content down, and cached copies expire. Follow these steps as soon as you become aware of the defamatory content:

1. Screenshot everything, including URL, timestamp, and surrounding context.
2. Use the Wayback Machine (web.archive.org) to submit a "save" of the page.
3. Download any video content using legitimate tools.
4. Print to PDF as well as image — PDFs preserve more metadata.
5. Note the date and time you discovered the content and any actions you took.
6. Do not contact the publisher before taking legal advice — pre-litigation conduct can affect your case.

Related reading: How to prove defamation under UK law | How defamation cases settle out of court | How much compensation can you get for defamation?