## Facts

- The case concerned a fatal road traffic accident involving a driver (the defendant) who held a valid licence and insurance.
- The defendant was involved in a collision with another driver who was under the influence of heroin.
- The prosecution argued that the defendant's presence on the road was a factual cause of the accident, as applying the 'but-for' test, the incident would not have occurred without his vehicle being at the scene.
- The defendant’s driving was otherwise entirely lawful and correct.
- The Supreme Court was asked to determine whether the defendant could be criminally accountable for the resulting death in these circumstances.

## Issues

1. Whether factual causation, established via the 'but-for' test, is alone sufficient for criminal liability.
2. Whether legal causation in criminal law requires the defendant’s actions to be a significant or more than minimal cause of harm.
3. Whether blameworthiness is a necessary component of legal causation for criminal accountability.

## Decision

- The Supreme Court held that factual causation, while necessary, is not alone sufficient to establish criminal liability.
- The Court clarified that legal causation requires the defendant’s conduct to be a major or more than minimal cause of the harm, not merely a background fact or trivial contribution.
- It was determined that legal causation also requires an element of blameworthiness in the defendant’s conduct.
- As the defendant’s driving was lawful and the principal cause of the accident was the victim’s own impairment, the conviction was overturned.
- The Court concluded that legal causation filters liability to ensure that sanction is reserved for blameworthy conduct with a strong connection to the harmful result.

## Legal Principles

- Legal causation in criminal law distinguishes between mere factual involvement and conduct that is a blameworthy, substantial cause of the outcome.
- The ‘but-for’ test alone establishes factual causation but does not suffice for criminal guilt.
- A more than trivial—that is, significant—contribution to the harm is required for legal causation.
- There must be a direct link between the defendant’s guilty conduct and the result for criminal accountability.
- The principle was affirmed and applied in subsequent case law, such as R v Taylor [2016] UKSC 5 and R v Bawa [2016] EWCA Crim 473, which stressed that the defendant’s breach or dangerous conduct must be a major cause of harm, not just part of the circumstances.

## Conclusion

R v Hughes [2013] UKSC 56 established that only conduct which is both blameworthy and a significant cause of harm meets the requirements of legal causation in criminal law. This decision clarified and shaped the distinction between factual and legal causation, influencing the interpretation and application of causation in subsequent criminal cases.
