Abolition of diminished responsibility

Diminished responsibility is a partial defence to murder which, if proven, reduces criminal liability for unlawful homicide from murder to manslaughter. This paper contends that given the vagueness, uncertainty and practical difficulties associated with the defence of diminished responsibility, it should be abolished completely in Australia as the very breadth of the defence, allows a coach and horses to be driven through criminal responsibility for murder. It will be contended that the availability of the defence of diminished responsibility is not appropriate even in jurisdictions such as Queensland and the Northern Territory which retain a mandatory life sentence for murder. Furthermore, it will be argued that attempts to reformulate the defence of diminished responsibility are akin to seeking to glue back together a shattered vessel.