McFerran v O'Connor – Re-affirming the “Just and Convenient” Test for Split Trials in Complex Personal-Injury Actions

Introduction

In McFerran v O’Connor ([2025] NICA 35) the Court of Appeal in Northern Ireland addressed the perennial question whether liability and quantum should be heard separately (“split trial”) or together in catastrophic injury litigation. The appellant – the first defendant van-driver – challenged an interlocutory decision of Colton J refusing to order a split trial. Three defendants (driver, Police Service of Northern Ireland and Northern Ireland Ambulance Service) face allegations of negligence after a tragic road collision in which the plaintiff suffered life-changing brain injuries and his partner died. The appeal required the Court of Appeal (Keegan LCJ, Horner LJ & Rooney J) to revisit the governing principles in Order 33 r.3 of the Rules of the Court of Judicature (NI) 1980 and the developing case-law on when, in the interests of justice, trials ought to be divided.

Summary of the Judgment

The Court of Appeal dismissed the first defendant’s appeal, upholding Colton J’s refusal to order a split trial. Key findings were:

The governing test remains whether it is “just and convenient” to split the trial, taking a broad and realistic view of all the circumstances (paras 18, 22).
Whether there is a “substantial prospect” that determining liability will dispose of the entire case is one relevant consideration, not a legal threshold (paras 23-25).
The appellate court will interfere with a discretionary case-management decision only on established Wednesbury-type grounds (error of law, consideration of irrelevant factors, etc.) (para 11).
Colton J had properly weighed delay, cost, complexity, prospects of settlement, the plaintiff’s brain injury, active case management and the multi-party nature of the claim. His decision therefore lay within the permissible “band of reasonable decisions” (paras 26-31).
A new argument advanced on appeal that the judge applied the wrong legal test was rejected as neither pleaded nor supported by the record (paras 22-24).

Analysis

1. Precedents Cited

Miller (A Minor) v Peoples [1995] NI 5 – Carswell LJ endorsed Lord Denning MR’s dictum that the default position is a unitary trial; separate trials are permitted whenever “just and convenient”.
Coenen & Payne [1974] 2 All ER 1109 – the seminal English authority from which the “normal practice” presumption arises.
Mohan v Graham [2005] NIQB 8 – Deeny J stressed the public-interest value of settlement and how splitting can sometimes hinder compromise.
McLean v McLarnon [2007] NIQB 9 – Stephens J introduced the “substantial prospect of disposing of the whole case” factor, while emphasising it was only part of the larger discretion.
Gibney v MP Coleman Ltd [2020] NIQB 68 and Electric Water v Philips [2012] EWHC 38 – provided a useful checklist of practical considerations when evaluating split trials (number of witnesses, overlap, delay, settlement, etc.).
Short Brothers PLC v AAR Corp [2025] NICA 18 and Flynn v Chief Constable of PSNI [2017] NICA 13 – outline the appellate standard of review for discretionary decisions.

The Court synthesised these strands to confirm there is no rigid formula; rather, a multi-factorial balancing exercise is required.

2. The Court’s Legal Reasoning

Standard of Appellate Review. Drawing on Short Brothers and Flynn, the Court reiterated that an appellate court may intervene only if the first-instance judge erred in principle or strayed outside the range of reasonable decisions (para 11).
Interpretation of Order 33 r.3. The statutory power hinges solely on what is “just and convenient”. The factors enumerated in earlier cases (cost, delay, settlement, complexity, prejudice, public interest) are guides, not preconditions (paras 14-19).
Relevance of the “Substantial Prospect” Factor. The appellant argued that Colton J elevated this factor to a mandatory hurdle; the Court found the judge merely treated it as important but not decisive, consistent with McLean (paras 24-27).
Complexity & Multi-party Liability. Three defendants each allege differing duties and breaches. The Court accepted Colton J’s assessment that a liability-only trial would be lengthy and unlikely to end the litigation, thereby negating anticipated savings (paras 27-28).
Catastrophic Brain Injury & Case Management. The plaintiff’s vulnerability justified heightened judicial supervision. Active management could mitigate delay without splitting issues (paras 25, 29).
Public Interest & Settlement. Though not expressly mentioned, the judge clearly considered these aspects; the Court held explicit reference was unnecessary (paras 26, 31).
Introduction of New Points on Appeal. The Court rebuked the appellant for raising an unpleaded “wrong legal test” argument, underscoring the importance of procedural discipline (para 22).

3. Impact on Future Litigation

Reaffirmation of Flexibility. The decision confirms that Northern Irish courts retain a broad discretion and will resist attempts to convert individual factors into hard thresholds.
Guidance for Catastrophic Injury Cases. Where liability is factually intricate and involves multiple defendants, the default of a combined trial will usually prevail, particularly to promote settlement and avoid duplication.
Practical Advocacy. Litigants seeking split trials must marshal concrete evidence of cost/time savings and demonstrate a realistic chance of obviating the need for a quantum hearing. Abstract assertions of delay will not suffice.
Appellate Strategy. Parties should ensure all substantive arguments appear in the notice of appeal; raising fresh, unargued issues risks summary rejection.
Case Management Culture. The Court’s express direction to list the matter for active management within days of judgment illustrates the judiciary’s commitment to expedition without resorting to bifurcation.

Complex Concepts Simplified

Split Trial: A procedural order directing that liability and damages (quantum) are tried separately. Intended to save time and cost where an early finding on liability may end the case.
Interlocutory Appeal: An appeal against a procedural or interim decision made before the final trial. The threshold for interference is higher because it involves judicial discretion.
Just and Convenient: A broad equitable standard empowering courts to adopt the procedure that best serves fairness, efficiency and the public interest.
Overriding Objective (Order 1 r.1A): The mandate that civil proceedings be conducted so as to secure expeditious, proportionate and cost-effective justice.
Substantial Prospect Test: A heuristic coined in McLean; not a strict rule, it gauges whether a liability-only hearing is likely to dispose of the action entirely. The Court of Appeal confirms it is merely one factor in the balancing exercise.

Conclusion

McFerran v O’Connor clarifies that the decision to split a trial in Northern Ireland remains rooted in the expansive “just and convenient” touchstone. While a realistic chance of disposing of the entire case at a liability hearing is highly relevant, it is neither a prerequisite nor determinative. The judgment also underscores the restrained appellate stance toward discretionary case-management rulings and highlights the importance of holistic, fact-specific analysis—especially in complex, multi-defendant, catastrophic injury litigation. Going forward, practitioners must present compelling, evidence-based submissions on all pertinent factors if they wish to depart from the default position of a unitary trial. The case thus strengthens procedural coherence and promotes efficient, fair adjudication in Northern Ireland’s civil justice system.