On 30 July 2015, Warby J gave judgment in the case of Lachaux v Independent Print following a trial of several preliminary issues in relation to a number of libel actions brought by Mr Lachaux.
For the purposes of this article, the facts of the case are not paramount but very briefly, the claimant is an aerospace engineer, a French national currently living and working in the United Arab Emirates. He brought libel actions against three different news publishers in respect of five articles first published between 20 January and 10 February 2014. Each of the articles complained of contained an account of events in the UAE, including proceedings against the claimant’s ex-wife, Afsana Lachaux, for ‘kidnapping’ the couple’s son. The articles reported allegations against the claimant each of which bears similar defamatory meanings about him.
This judgment was highly anticipated due to the fact that it would involve consideration by the judge on the question as to the meaning of the “serious harm” requirement in section 1(1) of the Defamation Act 2013. This section provides that:
“A statement is not defamatory unless its publication has caused or is likely to cause serious harm to the reputation of the claimant.”
The requirement that 'serious' harm to reputation has been or is likely to be caused, Warby J acknowledged, was clearly more demanding than the common law test identified in Thornton v Telegraph Media Group which required a tendency to 'substantially' affect in an adverse way people's attitudes to the claimant.
The key issue to be decided was whether on the proper construction of this section, a claimant has to prove either:
(a) that the offending words have a tendency to cause serious harm to the claimant's reputation; or
(b) that serious harm has in fact been caused or is likely to be caused.
It should be noted that this issue has been considered previously in two cases, by Bean J in Cooke v MGN Limited  in which it was accepted that evidence on the issue of harm was admissible and indeed may be necessary on the issue of whether serious harm has been caused and by Warby J himself in Ames v Spamhaus who adopted the same approach.
The claimant, pointing out that the judge was not bound by either of these cases, argued in favour of position (a), contending that s1(1) is solely directed to the meaning conveyed by the words. It was submitted that the new section does no more than "put into place an adjusted definition of the terms 'defamatory'", effectively raising the threshold of seriousness which had been identified in Thornton. Other than that, the overall structure of defamation law was to remain unaffected.
To hold otherwise, it was argued, would be to bring about radical changes to the structure of defamation law by abolishing the objective test of meaning; the single meaning rule; the 'tendency' test of what is defamatory; the rule that libel is actionable per se, and the presumption of harm.
The defendants, however, submitted that Cooke was rightly decided and that Bean J had been correct to conclude that 'has caused' requires a claimant to establish as a fact on the balance of probabilities that serious harm has been caused to his reputation and 'is likely to' requires proof that serious harm probably will be caused in the future. This argument focused on upon the construction of the words used in the Act. The defendants submitted that the mere fact that "has caused" and "is likely to cause" are presented as alternatives demonstrated that Parliament had explicitly chosen to depart from the common law approach of determining only whether the words had a defamatory tendency.
On the issue of the need for evidence relating to such harm, the defendants submitted that direct evidence would often be needed. Serious harm to reputation will in most cases, it was said, result in tangible adverse consequences. If no evidence of such consequences is adduced, the court should not draw an inference of serious harm. However, it was accepted that in some cases the court would be able to infer from the nature and extent of the publication complained of that serious harm has been or is likely to be caused.
Finding for the defendants, Warby reached the conclusion that in enacting section 1(1),
"Parliament intended to do more than just raise the threshold for defamation from a tendency to cause 'substantial' to 'serious' reputational harm. The intention was that claimants should have to go beyond showing a tendency to harm reputation. It is now necessary to prove as a fact on the balance of probabilities that serious reputational harm has been caused by, or is likely to result in future from, the publication complained of." 
The Judge rejected the claimant’s arguments that this interpretation of the Act involved imputing to Parliament an intention to revolutionise defamation law by implication as "alarmist and ill-founded" stating that he did not accept that his construction of s1(1) involves the dramatic consequences laid out before him.
Conflation of Thornton and Jameel
What appeared to weigh strongly in favour of the defendants was the fact that s1(1) was enacted in a context that already included the potential for claims to be struck out on the grounds of Jameel abuse.
The common law has already developed a twin-track approach to help prevent the proliferation of trivial defamation claims:
(a) they may fail to meet the threshold of seriousness identified in Thornton; or
(b) they may be struck out as an abuse of process pursuant to Jameel
The Jameel test already required as an assessment of all the circumstances of the case including, in particular, "the gravity in fact of the reputational harm that a publication has caused or is likely to cause." In other words, the Jameel test already allowed a judge to strike out on the basis that to allow it to proceed would amount to an abuse of the court's process because so little is at stake. This will often involve an in-depth scrutiny of the circumstances and evidence. In effect, a Jameel abuse application therefore already involved judicial consideration of whether there was sufficient benefit for "the game to be worth the candle" - i.e. whether a sufficient degree of harm had been done.
Warby J considered this twin track approach to be unsatisfactory and concluded that:
“The use in s 1(1) of the new language, ‘has caused or is likely to cause’ is consistent with an intention to simplify the law by drawing together the strands, and subsuming all or most of the Jameel jurisdiction into a new and stiffer statutory test requiring consideration of actual harm”. 
Presumption of Damage
Whilst Warby J had dismissed the majority of claimant's assertions that this interpretation of s1(1) had materially changed the structure of defamation law, he did accept that a requirement that a claimant must prove that serious harm had been caused or was likely to be caused would mean that "libel is no longer actionable without proof of damage, and that the legal presumption of damage will cease to play any significant role". However, he added that:
"to the extent that my construction does involve the implied repeal or amendment of common law principles, an intention to achieve this is, in my judgment, necessarily implicit in Parliament's choice of language." 
Warby J was also of the view that the emergence of the Jameel jurisdiction had already substantially eroded this common law rule - if indeed it had not eroded it entirely:
"Since Jameel it has no longer been accurate other than technically to describe libel as actionable without proof of any damage." 
Overall, his conclusion on the “serious harm” issue was that:
“by s 1(1) Parliament intended to and did provide that a statement is not defamatory of a person unless it has caused or will probably cause serious harm to that person’s reputation, these being matters that must be proved by the claimant on the balance of probabilities. The court is not confined, when deciding this question, to considering only the defamatory meaning of the words and the harmful tendency of that meaning. It may have regard to all the relevant circumstances, including evidence of what has actually happened after publication. Serious harm may be proved by inference, but the evidence may or may not justify such an inference” .
Whilst stressing that it was not necessary in this particular case to determine the secondary issue of the point in time from which the court should judge whether a statement "is likely to" cause serious harm, the judge indicated that he preferred the time at which the issue was determined rather than the date when the claim form was issued (when Bean J preferred in Cooke) .
Unless and until the Court of Appeal is persuaded to take a different view the position on this issue is now clear: section 1(1) requires proof of actual or likely serious harm to reputation. Warby J did not, however, regard this as being a particularly radical development for defamation law. This was perhaps due in part to his view that such serious harm may be proved by inference: "As recognised in Cooke and Ames, however, the serious harm requirement is capable of being satisfied by an inferential case, based on the gravity of the imputation and the extent and nature of its readership or audience. "
Another well-established common law rule is that the cause of action for libel and defamation actionable per se arises upon publication of the defamatory matter. Following Lachaux, this can no longer be treated as good law. The Judge accepted that "a consequence of s1 is that the status of a publication may change from non-defamatory to defamatory. A cause of action may lie inchoate until serious harm is caused or its future occurrence becomes probable.”