Introduction
The case of R v White [1910] 2 KB 124 remains a foundational authority on the issue of causation within the law of torts. Although originating in criminal proceedings, the decision is routinely examined in tort modules because it illustrates the application of the ‘but for’ test to factual causation. This essay outlines the facts and ratio of the case, evaluates its significance for tortious claims involving multiple potential causes, and considers its enduring limitations in establishing legal causation.
Factual Background and Ratio Decidendi
In R v White the defendant placed cyanide in his mother’s drink intending to kill her. She died shortly afterwards from a heart attack unrelated to the poison. The Court of Criminal Appeal held that the defendant could not be convicted of murder because the poison had not caused her death. Applying the ‘but for’ test, the court concluded that the mother would have died in precisely the same way even if the cyanide had never been administered. Tort scholars rely on this straightforward illustration to demonstrate that factual causation requires the claimant to prove, on the balance of probabilities, that the defendant’s act or omission made a difference to the outcome (see, for example, the discussion in standard tort texts).
Application to Tortious Causation
Within negligence and other torts requiring proof of damage, R v White supplies a clear template for the factual causation enquiry. Claimants must first satisfy the ‘but for’ test before questions of legal causation and remoteness arise. The case therefore continues to be cited when defendants argue that an independent medical condition or natural event would have produced identical harm irrespective of their breach. At the same time, the decision highlights the test’s potential harshness: where multiple factors operate, strict application may exonerate a defendant whose conduct contributed only marginally to the eventual injury.
Limitations and Interaction with Subsequent Authorities
Although R v White establishes the basic factual threshold, later authorities reveal its boundaries. In cases involving materially contributing factors or successive causes, courts have developed exceptions such as the ‘material contribution’ test articulated in Bonnington Castings Ltd v Wardlaw [1956] AC 613. These developments indicate that while R v White remains the starting point, it does not resolve causation where scientific certainty is impossible. Furthermore, the decision predates modern discussions of proportionate liability and the Fairchild exception, underscoring that factual causation is merely the first analytical stage.
Conclusion
R v White continues to shape undergraduate understanding of causation in tort by providing an accessible example of the ‘but for’ test. Its ratio reminds practitioners that liability will not attach unless the claimant can demonstrate that the defendant’s conduct was a necessary condition of the harm suffered. Nevertheless, the case also illustrates the limits of that test when confronted with complex or multiple causes, prompting the incremental refinement of causation principles in subsequent decades.
References
- R v White [1910] 2 KB 124.
- Bonnington Castings Ltd v Wardlaw [1956] AC 613.

