## Facts

- The defendant, a soldier, stabbed another soldier during an altercation at an army barracks.
- The victim was being carried to a medical facility but was dropped twice during transport.
- Upon arrival, the victim received negligent medical treatment; the medical staff failed to recognize a punctured lung.
- The victim died from his injuries.
- The issue arose as to whether the negligent treatment constituted a _novus actus interveniens_ (intervening act) that broke the chain of causation between the stabbing and the death.

## Issues

1. Whether the defendant’s act of stabbing remained an operating and substantial cause of the victim’s death despite the subsequent negligent medical treatment.
2. Whether the medical negligence was sufficient to break the chain of causation, thereby absolving the defendant of criminal liability.
3. What threshold must be met for an intervening act to sever the chain of causation in criminal law.

## Decision

- The court held that the defendant’s act was still an operating and substantial cause of death.
- The negligent medical treatment was not so overwhelming as to break the causal chain.
- The original stab wound remained a significant contributing cause of death, and criminal liability was upheld.
- The chain of causation will only be broken if the intervening act is so significant that the original act becomes merely part of the history.

## Legal Principles

- For criminal liability, the defendant’s conduct must be an operating and substantial cause of the harm; it need not be the sole or even the main cause.
- Medical negligence does not break the chain of causation unless it is so overwhelming that the original act becomes insignificant in causing death.
- A _novus actus interveniens_ must be an unwarranted and extraneous event which completely eclipses the defendant’s contribution for the causal link to be severed.
- Mere negligence or reasonably foreseeable complications from medical care will not normally constitute a _novus actus interveniens_.

## Conclusion

R v Smith [1959] 2 QB 35 confirms that criminal liability remains when the defendant’s conduct is an operating and substantial cause of the result, and subsequent negligent medical treatment will not break the chain of causation unless it is extraordinarily egregious and overwhelming in effect.
