Facts
- The claimant suffered severe complications following medical treatment provided by the Ministry of Defence.
- Multiple factors contributed to the claimant’s injury, including alleged negligent post-operative care as well as pre-existing conditions and other non-negligent factors.
- The claimant contended that the defendant’s negligence materially contributed to her injuries, even though the injuries had multiple causes.
Issues
- Whether the defendant's material contribution to the claimant’s injury was sufficient to establish liability in circumstances involving multiple causative factors.
- Whether the traditional "but for" test of causation is appropriate where harm arises from a combination of negligent and non-negligent factors.
- Whether precise quantification of the defendant’s role in the causation of harm is required for liability.
Decision
- The Court of Appeal held that a defendant may be liable if their negligence made a material contribution to the injury, even where other non-negligent factors were also causative.
- The Court found that the "but for" test is inadequate in cases involving multiple concurrent or sequential causative factors.
- The defendant’s contribution to the harm need not be the primary or dominant cause; it suffices if it is more than negligible.
- The Court confirmed that liability can be established without precise quantification of the defendant’s role, based on the overall evidence.
Legal Principles
- Where multiple factors cause harm, liability in tort may be established if the defendant’s negligence materially contributed to the injury, not just if it was the sole or principal cause.
- The traditional "but for" test may be set aside in favour of a material contribution test in complex causation scenarios.
- Material contribution requires the defendant’s conduct to be more than negligible, but does not need to be precisely quantified.
- This approach is particularly applicable in medical negligence cases and situations with complex or multifactorial causation.
Conclusion
Bailey v Ministry of Defence [2009] 1 WLR 1052 established that in tort law, a defendant’s material contribution to harm suffices for liability, providing a more flexible framework for causation in cases with multiple contributing factors, and particularly influencing claims in medical negligence and other complex contexts.