An accessory is a person who assists, but does not actually participate, in the commission of a crime. The distinction between an accessory and a principal is a question of fact and degree:

• The principal is the one whose acts or omissions, accompanied by the relevant mens rea, are the most immediate cause of the actus reus.
• If two or more people are directly responsible for the actus reus, they can be charged as joint principals. The test to distinguish a joint principal from an accessory is whether the defendant independently contributed to causing the actus reus rather than merely giving generalised and/or limited help and encouragement.