This allows the judge sentencing discretion, e.g. to impose a hospital order under section 37 of the Mental Health Act 1983 to ensure treatment rather than punishment in appropriate cases.
Section 2 of the Homicide Act 1957 states: (1) Where a person kills or is party to a killing of another, he shall not be convicted of murder if he was suffering from an abnormality of mental functioning which - (1A) Those things are - (1B) For the purposes of subsection (1)(c), an abnormality of mental functioning provides and explanation of D's conduct if it causes, or is a significant contributory factor in causing, D to carry out that conduct.
Voluntary intoxication will not satisfy the criterion that there must be an abnormality of mental functioning arising from a recognised medical condition (s.2(1)(a) Homicide Act 1957) and therefore cannot be relied upon as grounds for the partial defence.
The direction to a jury facing both diminished responsibility and drunkenness should be: and if the answer to that is yes, The more chronic forms of alcoholism and the long-term use of heroin and cocaine (see R v Sanderson[6]) can become a relevant factor where a craving for drink or drugs causes an abnormality of mind.
In R v Dietschmann,[8] the House of Lords held that where a defendant suffers from an abnormality of mind within s2(1) also consumes alcohol before the killing, the jury should find him or her guilty of manslaughter if they are satisfied that, notwithstanding the alcohol consumed and its effect, the abnormality of mind substantially impaired the mental responsibility for the fatal acts.