In McKenzie v Covidien LP [2026] CSOH 48 Lady Haldane has authorised the proposed representative party (“RP”) and granted permission for group proceedings to be brought on behalf of 83 individuals who all underwent hernia treatment using mesh products manufactured by Covidien.
Of additional interest to practitioners and businesses is the judge's observation that the Court of Session, including its appellate court, the Inner House, has now considered several applications to approve the appointment of RPs and to allow the RP to then bring group proceedings on behalf of a number of individuals, meaning we have a greater understanding of how the court will treat these applications. Read alongside Mackay v Nissan Motor Co Ltd 2025 CSIH 14, Milligan v Jaguar Land Rover Automotive plc 2025 CSIH 16, and Donnelly v Johnson and Johnson Medical Ltd [2025] CSOH 77, all of which were referred to in the court’s judgment, McKenzie provides a useful opportunity to take stock of how the relevant legal tests are being applied in practice.
The court rules
Group proceedings under Chapter 26A of the Rules of the Court of Session (“the Rules”) require the granting of two distinct applications before the proceedings can get fully underway: authorisation of the RP under section 20(3)(b) of the Civil Litigation (Expenses and Group Proceedings) (Scotland) Act 2018, and permission to bring the proceedings under section 20(5).
Rule 26A.7(2) of the Rules lists the factors which are to be considered by the court when deciding whether or not the proposed RP is a suitable person, and Rule 26A.11(5) sets out the circumstances in which permission may be refused, including if there is a lack of sufficient commonality, it has not been demonstrated that there is a prima facie case or real prospects of success, or it has not been demonstrated that group proceedings will be more efficient than individual court actions. The two applications are separate and, as Lady Haldane reiterates in McKenzie, do not necessarily stand or fall together. The decision whether to grant either or both applications is a discretionary one for the judge with which an appellate court will not lightly interfere.
Lessons from the line of cases
- Suitability is assessed holistically, not as a tick-box exercise. Mackay (at paragraph 77) sets out that an applicant need not satisfy each factor in Rule 26A.7(2) individually; the overriding question is suitability "in the round". McKenzie applies that approach. Mr McKenzie's lack of litigation experience, his use of a particular polyester mesh product different from those implanted in some other proposed group members, and unresolved questions of time bar, would be live issues for the litigation, but were not, the court held, impediments to appointment.
- The thresholds for prima facie case and real prospects of success remain low. Mackay described the prima facie test as requiring "no more than the appearance of a serious question to be tried" and the prospects-of-success test as “not an exacting one". Lady Haldane notes in McKenzie that this guidance from Mackay is authoritative.
- Commonality requires similarity, not identity. The statutory test is whether the claims to be brought by the group members raise issues that are the same, similar or related to each other. In McKenzie the proposed group members had different mesh products implanted to treat different types of hernia, but the court was satisfied that the overarching issues - whether the respondent manufactured and/or promoted the mesh products either negligently or whether they were not as safe as persons generally were entitled to expect – were sufficiently similar or related.
- Limits remain. In Donnelly the court refused permission for a hernia mesh group proceedings involving 17 claimants and five different products, on the basis that it was not persuaded that the applicant had demonstrated the practical benefits likely to flow from group procedure for those claims, as opposed to individual proceedings. The court noted, however, that the applicant would have been authorised as representative party had permission been granted. It is also important to note that the group in Donnelly consisted of 17 claimants compared with McKenzie’s 83, with the judge in Donnelly noting that where the number of claims is low, the relative advantage of group procedure over individual court actions is reduced (making it harder to pass the test). Conversely, in McKenzie, Lady Haldane noted that “there can be no doubt that attempting to pursue over 80 individual product liability cases, with the associated cost and complexity, giving rise to the possibility of conflicting decisions, depending where the cases are raised, is not commensurate with the efficient administration of justice”. Attempts to argue on behalf of the respondent in McKenzie that there was insufficient specification of alleged defects in the products, and therefore that (as had happened in Donnelly for a similar reason) permission should not be granted, were unsuccessful.
- Substantive legal points are largely for a later stage. Several of the respondent's more substantive points in McKenzie, including potential sub-grouping by mesh product, time bar, and the formulation of the group description, were acknowledged by Lady Haldane as “undoubtedly present[ing] challenges from a case management perspective”, but were expressly deferred to a hearing “further down the line” rather than treated as reasons to refuse permission. That has become a consistent feature of the post-Mackay decisions.
A maturing procedure
Taken together, Mackay, Milligan, Donnelly and now McKenzie show a body of authority that is recognisably settling. The thresholds to the pass the gateway tests for the appointment of an RP and the granting of permission to bring group proceedings are deliberately low, but they are not perfunctory. The gateway tests are an important aspect of the procedure, but as the courts have noted, even once they are passed, challenges can remain for later stages of the proceedings.
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