"The facts are entirely for you. The first factual decision should be whether the prosecution have satisfied you that what you are dealing with is one continuing event. If you are satisfied, then depending on the facts you find proved in relation to the defendant whose case you are considering, you would decide whether any of the propositions above were fulfilled and appropriate. If, however, it was, or may have been, 2 separated events, then you should decide the following issues: (a) whether there was one or two causes of death (b) when and where that, or those, injuries were caused (c) what part the defendant whose case you are considering actually played and depending what decision you come to on the cause of death and where those injuries were inflicted, you would then have a context into which to consider the actions and intentions of each defendant. Thus if you were not satisfied that the head injury was an additional cause of death, then your decision as to where you find the knife wounds to have been inflicted would affect the potential liability of those who were not present, or may not have been present, at that particular scene. It is essential to bear in mind that a defendant cannot be jointly responsible if you conclude in his particular case that: (a) his acts did, or may, have occurred, before [Marcus Hall] received any of this fatal injuries and there had been a clear disengagement and withdrawal; or (b) his acts did, or may have occurred, after [Marcus Hall] received all his fatal injuries and the acts did nothing to hasten death. Thus, if you conclude that there were 2 separate events then cause of death and place of injuries that resulted in death are of vital importance. To start on the steps to verdict in the case of any defendant you have to be satisfied on the facts as you find them that wherever the event occurred, he was there and part of a joint enterprise to inflict the injuries that actually caused death."
"True, it will be easier for the Crown to prove that B participated in the venture realising that A might wound with murderous intent if weapons are carried…..But that is a purely evidential difference, not a difference in principle."
"[I]n the absence of exceptional circumstances, something more than a mere mental change of intention and physical change of location by those associated who wish to disassociate themselves from the consequences attendant upon their willing assistance up to the moment of the actual commission of that crime. I would not attempt to define too closely what must be done in criminal matters involving participation in a common unlawful purpose to break the chain of causation and responsibility. That must depend upon the circumstances of each case but it seems to me that one essential element ought to be established in a case of this kind: Where practicable and reasonable there must be timely communication of the intention to abandon the common purpose from those who wish to dissociate themselves from the contemplated crime to those who desire to continue in it. What is "timely communication" must be determined by the facts of each case but where practicable and reasonable it ought to be such communication, verbal or otherwise, that will serve unequivocal notice upon the other party to the common unlawful cause that if he proceeds upon it he does so without the further aid and assistance of those who withdraw."