판결 이유
Where there are multiple possible causes of the claimant's injury, the burden remains on the claimant to prove on the balance of probabilities that the defendant's breach was a cause. Material increase in risk is not equivalent to material contribution to injury.
사실관계
A premature baby was given excess oxygen by a junior doctor who negligently inserted a catheter into a vein instead of an artery. The baby developed retrolental fibroplasia (blindness). However, there were several possible causes of the condition, only one of which was excess oxygen.
판결 요약
The House of Lords ordered a retrial. The trial judge had applied the wrong test by treating material increase in risk as equivalent to material contribution. With multiple possible causes, the claimant still needed to show on the balance of probabilities that excess oxygen caused the condition.
주요 인용문
"A plaintiff must prove not only negligence or breach of duty, but that such fault caused or materially contributed to his injury."
— Lord Bridge
후속 처리
Distinguished from Bonnington Castings (cumulative cause) and from Fairchild v Glenhaven (mesothelioma exception). Key authority on standard causation requirements.