At present in English legal system there are two homicide offences murder and manslaughter. For the most serious, murder proof of an intention to kill or cause serious harm is needed for a successful conviction. If a partial defence is used in circumstances, such as provocation or diminished responsibility, then the offence is one of voluntary manslaughter. However, if someone kills but did not intend to cause death or serious harm but there was a death then they are liable to be convicted of involuntary manslaughter. There are numerous criticisms attached to Involuntary manslaughter as it covers a wide range of behaviour which can cause death, although one of the most prosecuted common law offences it is not yet become subject to any statutory definition or change and is in need of reform.
Although Involuntary manslaughter is split up into two offences Gross negligence manslaughter and constructive/unlawful manslaughter a general criticism of involuntary manslaughter is that there are two major problems with the wide range of conduct covered by the offence. The offences range from cases which just fall short of murder where the accused was aware there was a risk of death or serious harm but did not intend to cause either to the victim (R v Wacker), cases where the person is a experienced professional who makes a small but serious mistake resulting in death ( R v Adomako) and cases whereby a minor assault can end in death (R v Mitchell). This leads to problems in sentencing and labelling, including the fundamental problem that many cases currently amounting to unlawful act manslaughter involve only minor fault on the part of the defendant, and therefore should not be described as manslaughter at all.
The law commission have also identified a problem specific to constructive manslaughter the stated it is wrong for a defendant to be liable for a death which he did not