“Manslaughter is unlawful killing without an intent to kill or do grievous bodily harm. Anybody who is party to an attack which results in an unlawful killing which results in death is a party to the killing… a person who takes part in or intentionally encourages conduct which results in a criminal offence will not necessarily share the exact guilt of the one who actually strikes the blow. His foresight of the consequences will not necessarily be the same as that of the man who strikes the blow, the principal assailant, so that each may have a different form of guilty mind, and that may distinguish their respective criminal liability. Several persons, therefore, present at the death of a man may be guilty of different degrees of crime - one of murder, others of unlawful killing, which is manslaughter. Only he who intended that unlawful and grievous bodily harm should be done is guilty of murder. He who intended only that the victim should be unlawfully hit and hurt will be guilty of manslaughter if death results.”
“… where two persons embark on a joint enterprise, each is liable for the acts done in pursuance of that joint enterprise, that that includes liability for unusual consequences if they arise from the execution of the agreed joint enterprise but (and this is the crux of the matter) that, if one of the adventurers goes beyond what has been tacitly agreed as part of the common enterprise, his co-adventurer is not liable for the consequences of that unauthorised act.”
“It seems to this court that to say that adventurers are guilty of manslaughter when one of them has departed completely from the concerted action of the common design and has suddenly formed an intent to kill and has used a weapon and acted in a way which no party to that common design could suspect is something which would revolt the conscience of people today … Considered as a matter of causation there may well be an overwhelming supervening event which is of such a character that it will relegate into history matters which would otherwise be looked on as causative factors.”
“Once encouragement or assistance is proved to have been given, the prosecution does not have to go so far as to prove that it had a positive effect on D1’s conduct or on the outcome: R v Calhaem[1985] QB 808 . In many cases that would be impossible to prove. There might, for example, have been many supporters encouraging D1 so that the encouragement of a single one of them could not be shown to have made a difference. The encouragement might have been given but ignored, yet the counselled offence committed. Conversely, there may be cases where anything said or done by D2 has faded to the point of mere background, or has been spent of all possible force by some overwhelming intervening occurrence by the time the offence was committed. Ultimately it is a question of fact and degree whether D2’s conduct was so distanced in time, place or circumstances from the conduct of D1 that it would not be realistic to regard D1’s offence as encouraged or assisted by it.”
“The court in that case [ie R v Anderson, R v Morris]did not call into question what had been said in Wesley Smith, and Lord Parker noted that it had been approved by the court in Betty. The court was not therefore resiling from the general statement that where a person takes part in an unlawful attack which results in death, he will be guilty either of murder or of manslaughter according to whether he had the mens rea for murder. But the court recognised that there could be cases where the actual cause of death was not simply an escalation of a fight but “an overwhelming supervening event”