Defining Suitability and Efficiency in Scottish Group Proceedings: Mackay v Nissan Motor Co Ltd & Ors

Introduction

This commentary examines the Inner House decision in Reclaiming Motion by Joseph Mackay against Nissan Motor Co Ltd and Others [2025] CSIH 14. It was the first substantial guidance from Scotland’s highest civil appeal court on the two-stage preliminary filter for group proceedings under the Civil Litigation (Expenses and Group Proceedings) (Scotland) Act 2018 (“the 2018 Act”) and Chapter 26A of the Rules of Court of Session (RCS 26A). The case arises from proposed multi-party claims by some 8,500 purchasers, owners and lessees of Nissan and Renault diesel vehicles alleged to contain prohibited defeat devices for nitrogen oxide emissions. The two key applications were (1) for authorisation of Mr Mackay as representative party, and (2) for permission to bring group proceedings. Both were granted by the Lord Ordinary and challenged on appeal by first-to-fifth defenders (the Nissan companies) and supported in part by sixth-to-tenth defenders (the Renault companies).

Summary of the Judgment

The Inner House refused to disturb the Lord Ordinary’s twin interlocutors authorising Mr Mackay as representative party and granting permission for group proceedings. It reaffirmed that both decisions are exercises of broad judicial discretion, reviewable only for misdirection in law, irrelevance or unreasonableness. On the representative party application the court held that “suitability” must be assessed holistically and that Mr Mackay satisfied the threshold: he was independent, had no conflicting interests, enjoyed robust external funding and was backed by an experienced legal team. On permission the court confirmed that the statutory tests – commonality of issues, prima facie case, superiority of group procedure and real prospects of success – were met. It cautioned against over-technical scrutiny at the preliminary certification stage, emphasising the 2018 Act’s policy aims of broadening access to justice, streamlining complex multi-party litigation, and deterring corporate misconduct.

Analysis

Precedents Cited

Bridgehouse v Bayerische Motoren Werke AG 2024 SC 270: first Inner House guidance on Scottish group procedure origins and certification tests;
SLC Multi-Party Actions Report (1996): foundational policy advocating representative party independence, absence of conflicts, and adequate financial resources;
Scottish Civil Courts Review (2009): endorsement of certification criteria—common issues test, superiority test and suitability of representative party;
Wightman v Advocate General for Scotland 2018 SC 388: interpretation of “real prospects of success” as requiring genuine, non-fanciful prospects;
Campbell v James Finlay (Kenya) Ltd 2022 SLT 751: similarity or relatedness of issues need not be identical across all group members;
Forsyth v AF Stoddard & Co Ltd 1985 SLT 51 and Thomson v Corporation of Glasgow 1962 SC (HL) 36: appellate review principles for discretionary decisions.

Legal Reasoning

The court began by underlining that sections 20 and 21 of the 2018 Act and RCS Chapter 26A confer broad case-management discretion on the Lord Ordinary, to be exercised with a pragmatic and policy-driven approach. It rejected overly formalistic readings of the certification rules at the preliminary stage.

Representative Party (RCS 26A.7): “Suitability” is the sole legal requirement; the six factors in RCS 26A.7(2) are matters to be weighed, not tick-box hurdles. Mr Mackay’s independence, absence of conflicts, personal stake, robust third-party funding and legal support network cumulatively justified authorisation. A restrictive interpretation would frustrate access to justice.

Permission to Bring Group Proceedings (s.20(6) & RCS 26A.11): four potential refusal grounds – lack of commonality, no efficient administration, absence of prima facie case or real prospects – were each addressed:

Common issues: purchaser, owner and lessee claims all turn on the presence of defeat devices in Euro 5/6 diesel engines; issues are “related” even if not identical;
Efficient administration: 8,000+ claims make individual suits impractical and contrary to statutory aim;
Prima facie case: low threshold—appearance of serious question to be tried; detailed relevancy/specification reserved for later pleadings;
Real prospects of success: genuine rather than speculative; less than probable success yet sufficient to pass the filter.

Impact

This judgment is landmark authority on preliminary certification in Scottish group proceedings. Key impacts include:

Clarifying that representative party suitability is a holistic, policy-driven assessment rather than rigid compliance with sub-criteria;
Affirming that the commonality test tolerates variation so long as issues are related;
Reinforcing the low thresholds for prima facie case and real prospects at the initial stage;
Encouraging expedited disposal of certification motions to realize the 2018 Act’s access-to-justice objectives;
Providing appellate review boundaries—error of law or unreasonableness only.

Complex Concepts Simplified

Representative Party: The single individual who brings and manages group proceedings on behalf of multiple claimants. Must be “suitable,” meaning capable, independent and without conflicting interests.
Commonality Test: All group claims must raise the same, similar or related questions of law or fact. Absolute identity of issues is not required.
Prima Facie Case: A preliminary showing that there is a serious question to be tried—no in-depth merits or procedural drills at this stage.
Real Prospects of Success: Prospects must be genuine (not fanciful). It is a low-level filter ensuring hopeless or frivolous claims are removed early.
Opt-In Procedure: Only those who expressly join the group register participate in the proceedings.

Conclusion

The Inner House’s decision in Mackay v Nissan Motor Co Ltd & Ors establishes definitive guidance on the preliminary certification of group proceedings under Scotland’s new multi-party action regime. It underscores the legislature’s policy to facilitate collective redress by setting accessible, low-threshold filters for representative party suitability and permission to proceed. Technical objections should not derail group certification; judicial discretion must be applied with an eye to efficiency, fairness and the broader goal of enhancing access to justice and corporate accountability. Future applicants and defenders alike will look to this precedent when navigating the early stages of group litigation in the Court of Session.