## Facts

- The claimant, a 13-year-old girl, was involved in a road traffic accident after stepping into the road from behind a minibus.
- The defendant, who was driving a car, struck the claimant and was found to have been driving too fast.
- The lower court initially assessed the claimant’s contributory negligence at 90%, later reduced to 70% upon appeal.
- The defendant appealed to the Supreme Court, disputing the apportionment and arguing that the claimant bore full responsibility for not checking for traffic before crossing.
- The Supreme Court had to determine both the existence and appropriate extent of the claimant’s contributory negligence.

## Issues

1. Whether the claimant’s actions constituted contributory negligence and, if so, to what extent damages should be apportioned.
2. How to properly balance the causative potency and blameworthiness of each party’s conduct in apportioning liability.
3. Whether the lower courts’ assessment of the claimant’s contributory negligence was excessive or outside a reasonable margin of disagreement.

## Decision

- The Supreme Court found that both the claimant and the defendant were negligent and that their actions contributed equally to the accident.
- The court held that apportionment requires consideration of both the causative potency and relative blameworthiness of each party’s actions.
- It decided the lower courts had apportioned too great a degree of responsibility to the claimant.
- The claimant’s contributory negligence was reduced to 50%, finding this reflected an equitable balance given the facts.
- The court reiterated that appellate interference with apportionment decisions is only justified if the lower court’s assessment is beyond reasonable disagreement.

## Legal Principles

- Contributory negligence involves both the causative potency of the parties’ conduct and their respective blameworthiness.
- Apportionment of liability is a qualitative, not quantitative, “rough and ready exercise.”
- Child claimants are assessed against a standard suitable for their age, but as they near adolescence, their responsibility increases.
- Appellate courts should only intervene in apportionment decisions where there has been an error of law or the decision falls outside reasonable disagreement.
- The case distinguishes between standards applied to children of different ages (as seen by comparison with Yachuk v Oliver Blais Co Ltd [1949] AC 386).

## Conclusion

The Supreme Court in Jackson v Murray [2015] UKSC 5 confirmed that contributory negligence apportionment requires a balanced consideration of blame and causation, applying an age-appropriate standard for child claimants and limiting appellate interference to instances of manifest error.
