Various Claimants v Mercedes-Benz Group AG & Ors

A stay pending an intended appeal is discretionary and fact-sensitive. The court must weigh the risk of injustice in granting or refusing it, the effect of postponement, the realistic prospect and consequences of the appeal, the utility of continuing, costs already incurred, possible wastage, delay, settlement prospects and the fair use of court resources. Earlier case-management directions may be changed when circumstances change. A reduced representative trial should proceed where it retains a real prospect of determining issues of principle, materially narrowing or resolving wider litigation, and that utility outweighs the costs and risks of delay. A party that succeeded at an earlier liability stage should not be compelled to participate in contingent further proceedings pending appeal, although it may elect to make submissions and become bound by resulting findings of law.

This was an application in the Pan-NOx group litigation to vacate the Quantum Trial listed for October 2026 and stay proceedings pending the claimants’ intended application for permission to appeal the defined-liability judgment, [2026] EWHC 1753 (KB). That judgment left Mercedes liable for vehicles containing the CTS device and PCD liable for vehicles containing the Split device, while most allegations against other manufacturers failed. The changed liability landscape substantially reduced the proposed sample and meant that the trial might proceed against Mercedes alone or Mercedes and PCD. The claimants and most defendants argued that a reduced trial would be wasteful and non-dispositive; Mercedes contended that it retained substantial utility in resolving quantum principles and promoting settlement. The central issue was whether the Quantum Trial should proceed, and against which defendants.

The application was granted in part. The Quantum Trial was permitted to proceed against Mercedes alone. PCD was excluded, and the stay otherwise applied to the non-Mercedes GLOs.

1. The court’s jurisdiction to stay all or part of the proceedings arose under its inherent jurisdiction, preserved by section 49(3) of the Supreme Court Act 1981, and its general case-management powers under CPR 3.1(2)(g). There were no fixed rules governing the discretion. The court had to consider all the circumstances, including the risk of injustice, the fair allocation of court resources and justice between the parties. In a stay pending appeal, the focus was on minimising risk by weighing the effect of postponement against the possibility of a different eventual outcome, as explained in HTC Corp v Nokia Corp [2013] EWCA Civ 1759.

2. The court assumed, without expressing a view on the merits, that permission to appeal had a realistic prospect of being granted and that the litigation landscape might change. Disruption to existing case-management directions was relevant but subordinate to choosing the effective and economical course in the circumstances then existing.

3. The reduced coverage of the remaining sample claimants was not decisive. The assessment was evaluative rather than a box-ticking exercise. The Mercedes-only trial still offered a real prospect of determining important issues of principle concerning recoverability of distress, contractual objectives, assessment dates, valuation, mitigation, credit for use, post-acquisition losses and double recovery. Determining those issues could materially advance, narrow or resolve wider litigation, avoid or reduce a future trial costing approximately £45 million, and make use of substantial resources already invested.

4. The court did not consider it appropriate to compel a defendant that had succeeded at the liability stage to participate in contingent quantum proceedings pending appeal. The non-Mercedes Lead Defendants could nevertheless make written or oral submissions. If they elected to participate, they and the relevant non-Mercedes Lead Claimants would be bound by the resulting findings of law.

5. PCD was not included because both the PCD claimants and defendants opposed participation, and the marginal additional utility of its sample did not justify the incremental cost. The Mercedes sample was sufficient to determine the principal legal questions.

This was a first-instance procedural decision. The judgment records the earlier defined-liability judgment in the same litigation, [2026] EWHC 1753 (KB), followed by the claimants’ intended application for permission to appeal and their stay application. No appellate decision on the present application is stated.