## Facts

- The defendant shot the victim in the leg and stomach.
- The victim received medical treatment, including insertion of a tracheotomy tube.
- The victim died nearly two months later from respiratory complications, with a post-mortem revealing narrowing of the windpipe near the tracheotomy site.
- It was argued that negligent medical treatment was a significant contributing factor to the victim’s death.
- At trial, the judge directed the jury to consider if the medical negligence was "grossly negligent" or reckless to break the chain of causation.
- The defendant was convicted of murder, and the central issue on appeal was whether the negligent medical treatment was sufficient to break the chain of causation between the shooting and the death.

## Issues

1. Whether negligent medical treatment following the initial injury can be considered an intervening act sufficient to break the chain of causation in criminal law.
2. Whether the level of fault in the medical treatment (i.e., gross negligence or recklessness) is relevant in determining causation.
3. Whether the trial judge’s direction to the jury regarding causation was appropriate.

## Decision

- The Court of Appeal found that the trial judge had erred by asking the jury to focus on the degree of fault or "gross negligence" in the medical treatment.
- The court held that the key issue is not the level of fault in the medical care, but the independence and potency of the intervening act.
- Despite the erroneous direction, the conviction was upheld as the defendant’s actions remained a significant cause of the victim’s death.
- The appeal was dismissed, with the Court concluding the jury would not have reached a different verdict if properly directed.

## Legal Principles

- For a third-party act, such as negligent medical treatment, to break the chain of causation it must be so independent and so potent in causing death that the defendant’s original act becomes insignificant.
- The level of fault (i.e., whether the treatment was grossly negligent) is not determinative; the focus is on the independence and contribution of the act.
- A mere failure to meet the standards of a competent doctor, or even a momentary lapse of concentration, does not suffice; only an "extraordinary" act that overshadows the original conduct can break the chain.
- The “significant contribution” test remains central—if the original act is still a significant cause of the outcome, liability persists.
- The principles set out in this case distinguish causation in criminal law from tort law, emphasizing culpability over compensation.

## Conclusion

R v Cheshire clarified that an original wrongdoer remains liable for a victim’s death unless an intervening act, such as medical negligence, is so independent and potent that it renders the defendant’s action insignificant. The ruling firmly established that in criminal law, the focus is on the causal potency of the intervention rather than its degree of fault, setting a high threshold for breaking the chain of causation in cases involving third-party medical treatment.


R v Cheshire [1991] 1 WLR 844