Causing controversy: interpreting the requirements of causation in criminal law and tort law

Gemma Turton and Sally Kyd

The offence of causing death by driving a motor vehicle on a road while uninsured, under section 3ZB Road Traffic Act 1988 (inserted in 2006), threw into sharp relief the question of what it means to ‘cause’ an outcome. The offence appeared to be one of double strict liability: the defendant need not be aware that they are uninsured, and there is no requirement of carelessness or dangerousness in the manner of their driving. The question arose, then, whether a defendant could be said to have ‘caused’ the death of the victim in circumstances where the defendant should not have been driving because they were uninsured, but the manner of their driving was beyond reproach and instead the victim was driving dangerously. In R v Hughes (2013) the United Kingdom Supreme Court (UKSC) held that a driver did not cause a death simply by virtue of driving their vehicle on the road when they should not have. Instead, the court held, there must be something properly to be criticised in the manner of their driving, that contributed to the death, although it need not reach the level of ‘careless’ driving.

In reaching this decision, one issue that troubled the court was that the victim was not an innocent victim and could not have recovered any compensation if he had survived injured. It remains the case, however, that negligence liability would not exist where the defendant’s driving was open to some minimal criticism but did not reach the level of a failure to take reasonable care. This case therefore raises questions about the relationship between criminal law and negligence, as well as wider issues of causation: what does it mean to ‘cause’ an outcome, and how and why does the answer differ in criminal law and tort law, and where liability is strict or fault-based? The ‘how’ question is descriptive but should not be overlooked; our experience teaching criminal and tort law is that students often fail to differentiate between the causal requirements in criminal law and negligence.

In our article in the Northern Ireland Legal Quarterly, we examine the divergences of approach to causation and their justifications. Some can be attributed to doctrinal differences, the place the causal inquiry occupies among the other elements of negligence and within the actus reus of a crime. Other influences include whether causation is a matter for a judge or jury and the all-or-nothing nature of criminal liability compared to the allocation of responsibility that takes place in negligence, which can readily recognise the shared responsibility of both the claimant and the defendant through the partial defence of contributory negligence. Negligence liability also more readily recognises a defendant as having made a causal contribution where their negligence merely accelerates an outcome, and this is reflected in the extent of the award of damages. On a deeper level, we suggest that, in order to understand how the goals and justifications of each branch of law are reflected in their respective causal requirements, we must distinguish between causal responsibility, moral responsibility, and legal responsibility.

Strict liability remains problematic; it is less clear where the balance between moral luck and blameworthiness ought to lie because the justifications for strict liability are less clear cut and more variable. We ultimately agree with the UKSC in Hughes that something more than causation in the sense of involvement is required, but we do not agree that the solution is to inject a fault element into the essence of what it means to cause an outcome. That approach confuses causal and legal responsibility and is difficult to reconcile with earlier cases involving strict liability in respect of pollution.

The clearer solution, in our view, would be to incorporate a remoteness test into strict criminal offences, requiring the court to address the question of whether the harm was within the wrong being addressed by the offence. This ‘harm within the wrong’ test would encourage courts to identify the purpose and scope of the offence and to clearly articulate the reasons for injecting an element of fault. As such, it has application beyond section 3ZB to other strict liability result crimes or constructive offences and will enable courts to ensure a defendant is convicted only where the harm they have caused is also within the wrong addressed by the offence.