Chan Wing-siu v The Queen  AC 168 was a landmark case in Hong Kong that dealt with the doctrine of joint enterprise and the mens rea required for conviction under the principle of parasitic accessory liability.
In this case, the appellants, along with two others, entered the home of two victims with the intention to collect a debt. Two of the attackers carried knives. One of the assailants, Tse, was left to guard the wife while the other two fought with the husband. The husband was stabbed and died, while the two attackers also suffered substantial injuries. The wife was not able to identify which of the two assailants stabbed her husband. As they were leaving, one of the attackers also slashed the wife across the head, but she could not identify who it was.
All three defendants were charged and convicted of murder under Chapter 212, Section 17 of the Offences Against the Person Ordinance (Hong Kong). The defendants Chan and Tse denied involvement in the stabbing of the husband, while Wong admitted to stabbing him in self-defence after being attacked with knives. All three defendants claimed that the husband had attacked them first.
The main issue in this case was whether foresight of the possibility that the principal may commit a crime that goes beyond the plan of the initial joint venture was sufficient mens rea to justify a conviction under accessory liability. The court held that it was sufficient for a conviction under the principle of joint enterprise or parasitic accessory liability that a defendant foresaw that the principal may commit an offence that goes beyond the plan, even if he did not intend that the offence be carried out. In other words, the doctrine of joint enterprise allowed for conviction of all participants in a crime if they foresaw the possibility of the crime being committed, regardless of whether they actively intended to commit the crime.
However, this approach to joint enterprise was later overturned by the UK Supreme Court in R v Jogee , which held that foresight alone is not sufficient to establish parasitic accessory liability. Instead, the prosecution must prove that the defendant had actively encouraged or assisted the principal offender in committing the offence.
You can learn more about this topic and other relevant case law with our Criminal Law notes.