Onsider the criminal liability of Ann, Dr. Con and North London Hospital for homicide. You may ignore any drugs offences.

Please read the following problem and answer the question.
Consider the criminal liability of Ann, Dr. Con and North London Hospital for homicide. You may ignore any drugs offences.
Ann, aged 18, goes to Vince s flat to supply him with heroin. Vince, aged 16, injects himself with double the normal amount of heroin. Ann injects herself with a normal amount. Vince becomes ill. Ann puts him to bed and attempts to look after him but does not call for an ambulance for fear of getting into trouble with the police. After several hours, Vince jumps out of the third floor window and is killed by the fall.
Ann goes back home where she lives with Brian. Brian has become very violent towards her. In addition to drug dependency, Ann has a nervous condition which causes extreme depression and anxiety. During the morning, they play a game of cards. Brian accuses Ann of cheating. She goes to the kitchen, sharpens a carving knife, returns to Brian and points it at his neck. Brian shouts at Ann,  You lunatic, you have no self-control, you re a mad junkie. He picks up a nearby pan and threatens to hit her on the head. Ann plunges the knife into Brian s throat. She then calls an ambulance. Brian is rushed to North London Hospital where Dr. Con gives him a blood transfusion of the wrong blood type. Dr. Con has already been on duty for 60 hours that week. Brian dies later that night.
Medical evidence suggests that both Vince and Brian might have lived had they received proper medical care. When Ann is interviewed by the police she says that she did not foresee Vince jumping from the window. In relation to Brian, she said that she only wanted to frighten him. North London Hospital senior management admitted they had over-worked Dr. Con but that it was necessary to save money.