A recent ruling by the Supreme Court has clarified a difficult aspect of the law around joint enterprise, which is the doctrine by which a person may be found guilty of another person's crime if each were acting together for a joint purpose.
The court has confirmed that to be guilty of the offence committed by the principal, the secondary parties must have intentionally assisted or encouraged the actual offence that was committed, and not just encouraged a crime in general and at the same time have foreseen the possibility of other, potentially more serious, offences being committed.
However, the court took care in its judgment to explain that the gateway for those who have been convicted as part of a joint enterprise to appeal their conviction will be limited, which will be of some comfort to the victims and the families of victims of these serious crimes.
In its unanimous judgment in the conjoined appeals in R v Joggee; Ruddock v The Queen  UKSC 8 the Supreme Court sought to clarify the proper construction of the law as it relates to joint enterprise and to correct the error created by the case of Chan Wing-Siu v The Queen  AC 168 and the numerous cases (including leading cases of both the Court of Appeal and the House of Lords) which interpreted and applied the principle over the 30 years that followed.
The law in relation to joint enterprise and secondary liability is designed to deal with the prosecution of two or more defendants where one defendant (the principal) intends to commit a crime and the second defendant (the secondary party) assists or encourages the principal to do so.
D1 and D2 agree to rob a bank. D2's only involvement is to fund the operation.
In this scenario both D1 and D2 would be guilty of robbery even though D2 was not present and played no role in the extraction of money from the bank. This is a simple example and the position in relation to the guilt of both D1 and D2 is unaffected by the Supreme Court's judgment.
The error caused by Chan Wing-Siu relates to what has become known as "parasitic accessory liability" and is demonstrated by the following example:
D1 and D2 agree to rob a bank (crime A). D2 knows that D1 is violent and foresees that if there is resistance shown by the bank staff in handing over money D1 might attack someone with the intention of causing them serious harm. D1 and D2 go into the bank and during the robbery D1 attacks the bank manager causing him serious injury and the manager later dies (crime B, murder).
The case of Chan Wing-Siu made D2 guilty of crime B because he had foreseen the possibility that D1 would commit murder and, having done so, his continued participation in crime A (the robbery) was taken as automatic authorisation of crime B (the murder), rather than simply evidence that he intended to assist or encourage crime B.
Some might initially struggle to see the problem with this and say that criminals who set out together to commit crime should be punished to the same extent regardless of what follows. However, Chan Wing-Siu created a situation where D2 would be guilty of murder for foreseeing the possibility of its commission by D1 and nevertheless giving assistance or encouragement to the robbery, rather than requiring him to have the necessary intention to assist or encourage murder. In contrast, in order to convict D1 of the murder, it would have to be proved that he intended to murder. As a result of Chan Wing-Siu, a lower threshold for D2's guilt had been created in circumstances where he had in fact not been the one who had carried out the attack;
The Supreme Court, in a judgment that revisited and considered in detail the key Court of Appeal, Privy Council and House of Lords decisions over the past 30 years, has corrected this problem by deciding that, in this example, for D2 to be guilty of murder he must have intentionally assisted or encouraged D1 to commit the offence which D1 in fact commits.
The Supreme Court took care in its judgment to explain that this does not mean that every person who has been convicted as part of a joint enterprise will now be able to appeal their conviction.
Not only is there a very narrow gateway for defendants to seek permission to appeal in these circumstances, but also they will not be assisted if their case is one in which intention is plainly not an issue, such as where their conduct during the commission of the offence is strong evidence from which it could safely be inferred that their intention was to assist or encourage the offence that was actually committed. For example, if D1 and D2 go to a bank, both armed, with the intention of robbing a bank and D1 shoots and kills someone, it may be perfectly proper for a jury to infer that D2 possessed the intention that the firearms would be used if resistance was met, there being no other lawful reason to carry a gun.
Although joint enterprise regularly features in cases involving serious violence it is also relevant in cases of fraud and financial crime. Its wider implications should not be underestimated and may now mean that Parliament takes steps to create or amend legislation to address these issues, including through reform of sentencing and, in particular, mandatory life sentences.
In the meantime, it is clear that the Supreme Court is not afraid, in the right circumstances, to tackle important matters in an effort to bring clarity to what is undoubtedly a complicated, emotive and fiercely debated area of law.