## Facts

- Mr. Johns negligently caused a traffic accident near the exit of a tunnel, blocking a lane.
- Two police officers arrived at the scene to manage the incident.
- The second police officer negligently failed to close the tunnel to oncoming traffic and subsequently ordered the claimant (another police officer) to ride his motorcycle against the flow of traffic to close the tunnel.
- While following this order, the claimant was struck and injured by a third negligent driver.
- The trial judge initially held Mr. Johns solely liable for the claimant's injuries.
- On appeal, the Court of Appeal reassessed the causal chain and the allocation of liability.

## Issues

1. Whether the negligent order given by the second police officer to ride against oncoming traffic constituted a novus actus interveniens breaking the chain of causation between Mr. Johns's original negligence and the claimant's injury.
2. Whether the consequences of the second police officer’s actions were reasonably foreseeable as a result of the initial negligence.
3. The extent to which liability attaches to the original tortfeasor when a rescuer is injured as a result of an intervening act of negligence.

## Decision

- The Court of Appeal held that the negligent, affirmative order by the second police officer was a novus actus interveniens, breaking the causal chain and relieving Mr. Johns of liability for the claimant’s injuries.
- The court found that the negligence of the police officer’s command was not a reasonably foreseeable outcome of the original accident.
- As a result, liability for the claimant’s injuries rested with the second police officer rather than with Mr. Johns.
- The court distinguished between passive omissions and positive acts, holding that the latter are more likely to constitute a breaking of causation.

## Legal Principles

- Novus actus interveniens: A new, independent, and significant act—particularly a positive act of negligence—may break the chain of causation in tort law, absolving the initial wrongdoer of further liability.
- Foreseeability: Liability does not extend to every remote consequence of negligence but is limited to outcomes reasonably connected and foreseeable from the original wrongful act.
- Rescuer principle: The original tortfeasor may not be liable for injuries sustained by rescuers when a subsequent, independent act of negligence intervenes.
- The distinction between omissions and positive acts is relevant; positive negligent acts are more likely to break the chain of causation.

## Conclusion

Knightley v Johns clarifies that when an unforeseeable, independent act of negligence occurs—especially a positive act such as a negligent command by an intervening party—it may break the chain of causation, limiting the original tortfeasor’s liability. The decision reinforces the significance of foreseeability and the nature of intervening conduct in determining responsibility for damages in negligence cases.


Knightley v Johns [1982] 1 WLR 349