Bailey & Ors v GlaxoSmithKline [2019] EWCA Civ 1924

The Court of Appeal summarised rulings on the legality of pursuing a “worst in class” approach to defectiveness for the purposes of the Consumer Protection Act 1987.

Full judgment, dated 8 November 2019


This case arose out of a Consumer Protection Act 1987 claim concerning the addictive effect of an SSRI drug. The Claimant limited its case (the court ruled) to a “worst-in-class” approach to defectiveness, i.e. it attempted only to demonstrate that the SSRI in question was worse than its competitors. The Claimant was not, therefore, permitted to invite the court to conduct a wider risk/benefit analysis of the drug as a whole. As well as ruling that the Claimant was limited to such an approach, the court appeared to indicate that such an approach was not enough, and that in CPA claims defectiveness was only to be judged by a wider risk/benefit approach.


This appeal arose out of several Claimants bringing a claim for personal injuries against the Defendant as the manufacturer of Seroxat, an SSRI, on the basis that it was addictive and caused unpleasant withdrawal symptoms. The claim was brought under section 3 of the Consumer Protection Act 1987 (“the Act”).

The procedural basis of this claim was extremely complicated. In short, the appeal was against a ruling of the trial judge as to the scope of the Claimant’s case on defect. The dispute was whether the Claimant’s case on defect was limited to the “worst-in-class” approach – namely, that Seroxat caused more significant and/or unpleasant withdrawal symptoms than other similar drugs – or whether the Claimant was permitted to invite the judge to consider a risk/benefit analysis of Seroxat and determine thereby that the drug was defective.

Hamblen LJ gave the judgment of the court. At paragraphs 4-8 he set out e legal provisions and authorities that governed the application of the section. Of particular importance is the judgment of Hickinbottom J in Wilkes v DePuy International Limited [2018] QB 627, where he said “any assessment of its safety will necessarily require the risks involved in use of that product to be balanced against its potential benefits including its potential utility”. (8)

At paragraphs 9-28 Hamblen LJ summarised the pleadings and procedural background and at paragraphs 29 onwards he gave the ruling of the court that the appeal was dismissed, because as a matter of fact both the trial judge and Foskett J had previously ruled that a risk/benefit analysis was not within the scope of the trial. Accordingly, it was not open to the Claimant to raise it at trial and their case was limited to the “worst-in-class” approach.

Although the decision itself is only really of significance to the parties involved, the discussion and the context of the litigation strongly suggests that when bringing a claim under the Act it is necessary to plead and evidence an objective (i.e. not merely relative to competitors) risk/benefit analysis that weighs in your favour. The “worst-in-class” approach would not appear to be enough.

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