<P> But although this may apply to the generality of offences, "constructive manslaughter" is different . R v Lowe (1973) QB 702, the defendant committed the offence of neglecting his child under s1 Children and Young Persons Act 1933, and this caused the child's death . It was held that there should be a difference between commission and omission . Mere neglect without some foresight of the possibility of harm resulting is not a ground of constructive manslaughter, even if that omission is deliberate . R v Khan & Khan (1998) CLR 830, confirmed that there is no separate category of manslaughter by omission unless the omission constitutes a breach of duty to act . The defendants supplied a 15 - year - old prostitute with twice the amount of heroin likely to be taken by a regular user . The defendants left her unconscious in the flat, returning the next day to find that she had died of the overdose . Had medical assistance been called, the girl would probably not have died . The unlawful act was supplying the drug but the death was caused by the quantity injected by the victim . The trial judge invited jury to consider liability on the basis of the defendants' failure to summon medical assistance . On appeal, the conviction was quashed because the brothers had not accepted a duty to act before she took the heroin . </P> <P> In general terms, doctors and hospitals have a duty to provide appropriate care for their patients, and an omission may breach that duty except where an adult patient of ordinary capacity terminates the duty by refusing consent . There is a conflict in public policy . The policy of patient autonomy enshrines a right of self - determination--patients have a right to live their lives how they wish, even if it will damage their health or lead to premature death . Society's interest is in upholding the concept that all human life is sacred and should be preserved if at all possible . It is now well established that the right of the individual is paramount . In Re C (Adult: Refusal of Treatment) (1994) 1 WLR 290, a patient diagnosed as a chronic, paranoid schizophrenic refused to allow his gangrenous foot to be amputated . This was permitted because his general capacity showed him capable of understanding the nature, purpose and effect of the life - saving treatment . In Re B (Adult: Refusal of Medical Treatment) (2002) 2 AER 449 the presumption that an adult has full capacity can be rebutted if: </P> <Dl> <Dd> (a) the person is unable to understand the information relevant to the decision, especially as to the likely consequences of having or not having the treatment; or </Dd> <Dd> (b) the patient is unable to use the information and weigh it in the balance as part of the process of arriving at a decision . </Dd> </Dl> <Dd> (a) the person is unable to understand the information relevant to the decision, especially as to the likely consequences of having or not having the treatment; or </Dd>

When does the criminal law punish a failure to act