Neil Rowe, senior in-house counsel at THEMIS Clinical Defence, considers the latest Court of Appeal ruling on causation.

In Zgonec-Rozej v Pereira [2025] EWCA Civ 171, the Court of Appeal reaffirmed a fundamental principle of clinical negligence law: that the doctrine of material contribution is of limited applicability, arising only where the court is unable to determine causation on a but-for basis. 

Although the case arose from a psychiatric context involving suicide, the court’s reasoning has general application across all areas of clinical negligence.

The judgment also highlights the difficulties that courts face when the claimant settles out of court with some, but not all defendants before trial, leaving one party to defend their actions in isolation. 

Finally, the case includes some interesting comments on contributory negligence, a defence that does not often arise in clinical negligence cases.

Facts

Mr John Richard William Day Jones was a renowned human rights barrister, previously head of Doughty Street Chambers. He unfortunately suffered from mental health issues in 2016, receiving voluntary inpatient psychiatric treatment at the Nightingale Hospital London under the care of consultant psychiatrists Dr Bakshi and Dr Pereira. Tragically, he died after stepping in front of a train at West Hampstead station. 

The claim, brought by Ms Misa Zgonec-Rozej (his partner and executor of his estate), alleged negligence in risk assessment, discharge planning, and follow-up care causing his suicide. She sought damages of £5 million.

Three defendants were initially named, the hospital, Dr Bakshi and Dr Pereira. The claimant settled with the hospital and Dr Bakshi just before trial, without admission of liability and for undisclosed sums, leaving Dr Pereira as the only defendant to face the claim at trial. The High Court noted that if the claim against Dr Pereira was successful it was valued at £1.75 million less the settlements reached with the hospital and Dr Bakshi. 

The court found in Dr Pereira’s favour, concluding that while there had been breaches of duty, including a failure in the holiday handover to Dr Bakshi leading to delay, the claimant had not proven causation under the but-for test. In other words, even if the treatment had not been negligent, Mr Jones would still have taken his life. 

The claimant appealed, inviting the Court of Appeal to apply the material contribution test on the basis that the complicated overlapping factors that led to the suicide in this (and similar cases) were the paradigm for the application of that test. The claimant also appealed the findings on contributory negligence. 

The judgment

Clear rejection of the material contribution test: The court at first instance found that despite the complex web of factors which may lead to or prevent suicide, on the evidence available it was possible to determine causation on the balance of probabilities. Accordingly, the doctrine of material contribution had no role to play.

In the Court of Appeal, the claimant’s argument was entirely rejected. It was reaffirmed that the but-for principle is the primary mechanism for determining factual causation in the law of tort. Material contribution is a recognised exception to this – Bailey v MOD [2009] 1 WLR 1052 and Williams v Bermuda Hospitals Board [2016] AC 888 – but its scope is limited. 

Accordingly, the claimant was required to prove that but for the negligence, the death would not have occurred. The court found the evidence too speculative to support that conclusion and upheld the trial judge’s decision. It was not necessary to enter an analysis of whether Mr Jones’s death by suicide constituted a divisible injury, or a single, indivisible outcome, where amongst cumulative causes the breach of duty more than negligibly contributed to the outcome.

Procedural difficulties from partial settlements: Because the claimant had settled with the hospital and Dr Bakshi before trial, they did not attend court to give evidence, and there was no evidence before the court as to the merits or demerits of Dr Bakshi’s treatment of Mr Jones. It followed that a finding that Dr Pereira’s inadequate handover to Dr Bakshi caused or materially contributed to the death could not properly be made. Such a finding would necessarily rely on the Court making findings of fact as to what Dr Bakshi would have done but-for the defendant’s breach – a question which had not been tried.

At the appeal, the Court of Appeal confirmed in such circumstances a trial judge would be entitled to decline to find causation on the basis that to do so would be to speculate on issues which had not been tried.

Contributory negligence: Contributory negligence is not often pleaded in defence to a claim of clinical negligence given that the vast majority of claimants are following treatment plans when an adverse incident occurs. However, psychiatric cases will often involve patients who have sufficient autonomy to make decisions not to follow recommended treatment and, for example, abscond and self–harm or commit suicide. 

In this case, the High Court did not rule on contributory negligence as the claim had failed on causation, but the Judge made some observations. Having reviewed the evidence, including Mr Jones interacting calmly with staff earlier that day, as captured on CCTV, and making a telephone call shortly before taking his own life, it was found that while Mr Jomes was clearly very unwell, his illness had not overruled his autonomy and a reduction of damages of 25% would have been appropriate. 

Unfortunately, whilst evidence was given on the key issue of the deceased’s state of mind at the point of death, including in this case the absence of a suicide note, the Court of Appeal did not determine this point, again because the claim had failed on causation. 

The impact

This judgment is not ground-breaking but has wide-reaching application across the healthcare and legal landscape:

Causation thresholds reinforced: Claimants in medical negligence cases must meet the traditional but-for standard. Courts will not lower that bar by applying the material contribution test unless it is not possible to reach a conclusion on the but for test. Claimant solicitors should be wary of indiscriminately pleading material contribution where it is inappropriate.  

Broad relevance beyond psychiatry: Though the case involved suicide, its principles apply across all branches of medicine, including general practice, surgery, oncology, emergency medicine, and maternity care.

Contributory negligence affirmed: On the appropriate facts, contributory negligence remains an available defence in clinical negligence cases. 

Caution against isolated trials: Defendants, insurers, and claimant lawyers alike should be alert to the strategic and evidential risks of settling with some parties while continuing against others. Doing so may hamper the court’s ability to fairly assess causation, or reduce the prospects of success against the remaining defendant.

Conclusion

Zgonec-Rozej v Pereira [2025] EWCA Civ 171 is a significant reaffirmation of a key legal boundary: if the court can determine causation of injury and death on the but-for basis there is no need to consider the material contribution test. Defendant practitioners will be relieved that the Court of Appeal was not tempted to take the opportunity to allow creep of the material contribution test, given the potential ramifications. 

The case also provides a useful example of when contributory negligence may arise in clinical negligence and the evidence required to prove it and underlines the strategic and evidential complexities that arise when claims are resolved against some defendants but not others and the matter proceeds to trial. For practitioners, providers, insurers, and lawyers, the judgment serves as a welcome reassertion of the relevant test of causation and a cautionary note on navigating complex medical litigation.