Reeves v Commissioner of Police of the Metropolis [2000] 1 A.C. 360

Martin Lynch was held in police custody and was known to be at risk of suicide after previous attempts. Medical advice called for frequent observation. Police left a cell feature accessible which should have been secured, and Lynch used the opportunity to harm himself fatally between checks. His partner brought a claim under the Fatal Accidents Act 1976. The police accepted a duty to take reasonable care to prevent this harm and accepted breach. The dispute concerned whether Lynch's deliberate act broke causation and whether his own responsibility could reduce damages.

• Was C’s partner’s suicide attempt an intervening act that broke the chain of causation between D’s breach of duty and the death?
• Was the suicide attempt a negligent act contributing to the death of C’s partner, and thus reduce the damaged awarded?

Owing to the complete control that the police exercised over prisoners in custody and the stresses inherent in the custodial situation, the police owed a duty to prevent such people from self-harm. The duty represented an exception to the general rule that a deliberate act by a person of sound mind taking advantage of the defendant’s negligent act would destroy the causative link from the breach of duty. Both the police, who had been negligent in leaving the hatch open, and C’s partner, who had responsibility for his own life, were the causes of the death. As such, C’s partner was held contributorily negligent, and damages were reduced by 50%. While the finding that the deceased was of sound mind will be questioned, it is how prior judges proceeded on the evidence and we must accept that evidence. This means there is no basis of diminished mental capacity that would minimise the deceased’s share of responsibility. Moreover, the contribution which he made was clearly substantial. It being done within minutes of the last check of the cell indicates his determination to seize the opportunity immediately before the next check.

Where a defendant owes a duty to take reasonable care to prevent particular deliberate self-harm, that very act does not necessarily break the causal chain. In Reeves the police remained liable, while the deceased's own responsibility justified a 50 per cent reduction for contributory fault.

Reeves connects causation to the purpose of the duty. A duty to protect a known vulnerable detainee would lose much of its meaning if the anticipated self-harm automatically defeated liability. At the same time, preserving the causal chain did not make the deceased's conduct irrelevant to apportionment. Distinguish a complete intervening-cause defence from a reduction under the Law Reform (Contributory Negligence) Act 1945. The particular custodial duty was accepted; the case does not establish an unlimited duty to prevent all self-harm.