Zgonec-Rozej & Ors v Pereira: Clarification of the Primacy of the “But For” Test in Negligence

Introduction

This case, Zgonec-Rozej & Ors v Pereira ([2025] EWCA Civ 171), arose from the tragic death of Mr. John Jones QC while he was an inpatient at the Nightingale Hospital in London. His wife and children sued Dr. Pereira, the admitting consultant psychiatrist, over alleged negligence in his psychiatric care—particularly regarding handovers, treatment planning, and the failure to provide prompt psychotherapy.

The key issues before the Court of Appeal included whether Dr. Pereira’s admitted breaches of duty in patient care and communication caused or materially contributed to Mr. Jones’s death, and whether a contributory negligence finding was justified. The central legal question revolved around the scope of “but for” causation versus the “material contribution” principle—a crucial aspect of medical negligence law.

Ultimately, the Court of Appeal dismissed the appeal, confirming that because the trial judge was able to decide factual causation on a “but for” basis, the doctrine of material contribution did not apply. This judgment provides important clarification on when the “material contribution” exception can be invoked in negligence proceedings, and it underscores the significance of thorough evidential support in establishing causation.

Summary of the Judgment

The Court of Appeal upheld the trial judge’s conclusion that although there were three separate breaches of duty by Dr. Pereira, none of those breaches was proven—on a balance of probabilities—to have caused or contributed to Mr. Jones’s death. Specifically:

Dr. Pereira’s failure to inform Mr. Jones of his forthcoming three-week absence did not, by itself, contribute to the fatal outcome.
The inadequate handover to Dr. Bakshi was indeed negligent, but there was insufficient evidence to show that this omission caused Mr. Jones measurable harm.
The delay in securing prompt one-to-one psychotherapy may have denied Mr. Jones some potential benefit, but the Court was not persuaded that this breach probably altered the tragic outcome.

Consequently, the Court concluded that the “but for” test could be addressed directly; material contribution—an alternative approach where causation cannot otherwise be discerned—was deemed inapplicable given the trial judge’s findings.

Analysis

Precedents Cited

Several noteworthy authorities were referenced:

Hotson v East Berkshire Area Health Authority [1987] AC 750: Lays out the requirement for establishing causation on a balance of probabilities in medical negligence cases.
Bailey v Ministry of Defence [2009] 1 WLR 1052: Addresses the principle that when the precise chain of causation is scientifically indeterminable, and the negligent factor is more than de minimis, the court may apply a modified “material contribution” test.
Williams v Bermuda Hospitals Board [2016] UKPC 4, [2016] AC 888: Sheds further light on when the material contribution principle applies, emphasizing that it arises only where the “but for” test cannot be applied satisfactorily.
Corr v IBC Vehicles Limited [2008] 1 AC 884 and Reeves v MPC [2000] 1 AC 360: These cases guided the court’s determination of contributory negligence, especially in instances involving suicide and the individual’s level of mental autonomy at the time of the fatal act.

The Court of Appeal ultimately reaffirmed that if the court can determine factual causation using the “but for” test, the need for the “material contribution” principle falls away.

Legal Reasoning

The trial judge had found three distinct breaches by Dr. Pereira:

Not telling Mr. Jones he would be away for three weeks immediately after arranging the admission.
Failing to provide a sufficiently comprehensive handover to Dr. Bakshi.
Delaying the process of arranging one-to-one psychotherapy upon his return.

Nonetheless, the court undertook a robust “but for” analysis to test whether any of these breaches was the factual cause of Mr. Jones’s death. The judge concluded that, on the evidence available:

Neither the lack of a warning about Dr. Pereira’s leave nor the poor handover likely led to Mr. Jones’s deterioration, particularly because the evidence about Dr. Bakshi’s subsequent treatment was not before the court.
Even had the patient received psychotherapy slightly earlier, it could not be stated on the balance of probabilities that it would have prevented him from taking his life.

Turning briefly to the “material contribution” principle, the Court noted that it only applies if “but for” analysis does not suffice. Here, because the judge was able to make a definitive “but for” finding (i.e., concluding that it was not more likely than not that the breaches caused death), there was no recourse to applying a material contribution analysis.

Regarding contributory negligence, the judge reasoned that Mr. Jones had retained sufficient autonomy to be responsible for his own actions, though severely impaired by his mental condition. If the doctor had been found liable, the judge would have attributed a 25% reduction to the overall award based on Mr. Jones’s act in taking his own life. Since liability was never established, the issue of contributory negligence proved moot.

Impact

This judgment carries important implications for:

Medical Negligence Causation: The decision reiterates that courts should, where possible, resolve causation questions with the conventional “but for” test. The “material contribution” doctrine remains a limited exception, available only when “but for” analysis is not feasible.
Clinical Handover Standards: The court confirmed the necessity of providing adequate case notes and direct handover to successor clinicians. While breaches will be taken seriously, liability will not necessarily attach unless there is clear causal evidence tying those breaches to harm.
Continuity of Care: Psychiatric practitioners should be aware that taking leave or facing scheduling emergencies does not absolve them from ensuring proper transitions in patient care. This case highlights the importance of thorough communication among psychiatric professionals.
Contributory Negligence in Cases of Suicide: Where a patient, owing to underlying illness, lacks full autonomy, courts will proceed with caution when attributing responsibility. However, if the patient exhibits rational functioning and clear intent, contributory negligence might be applied, albeit in a measured way.

Complex Concepts Simplified

1. The “But For” Test: In negligence law, this test asks whether the harm would have happened “but for” the defendant’s negligent act. If the harm would still have happened anyway, the defendant is not liable.

2. Material Contribution Principle: This is an exception often raised where causation is scientifically uncertain. If negligence contributed in more than a minimal (i.e., non-trivial) way to the harm—even if it cannot be stated definitively that “but for” the negligent act the harm would not have occurred—the court may find liability under this doctrine. However, this is only resorted to when “but for” causation genuinely cannot be established on the evidence.

3. Contributory Negligence in Suicide Cases: Normally, if someone commits an act that contributes to their own harm, the court may reduce the damages recoverable. In the context of psychiatric conditions, courts must consider whether the individual fully understood and controlled their actions or was so impaired as to lack autonomy and hence fault.

Conclusion

Zgonec-Rozej & Ors v Pereira clarifies that if a court can resolve factual causation through conventional “but for” analysis, the “material contribution” approach does not apply. Despite the finding of breaches of duty by Dr. Pereira, the claims could not succeed because the evidence did not demonstrate that these breaches (>50% more likely than not) caused or materially contributed to Mr. Jones’s decision to end his own life.

The judgment serves as a reminder to all medical professionals—especially those involved in psychiatric care—of the utmost importance of transparent communication and proper clinical handover. Yet it also emphasizes that establishing liability demands clear, direct evidence linking negligent acts to a patient’s harm. For legal practitioners, the case reaffirms how the courts prioritize “but for” analysis and address the “material contribution” principle only where strictly necessary.

In the broader legal context, Zgonec-Rozej & Ors v Pereira reaffirms and illustrates key principles on causation in medical negligence. By underlining how the “but for” test predominates when its application is feasible, it offers a helpful precedent on how judges should approach—and at times limit—material contribution arguments where factual causation can be established through orthodox means.