TThe defence for diminished responsibility was introduced by the Homocide Act 1957, Section 2. This replaced the defence for insanity even though this law still exists the test was too narrow to include many of the mental problems people can suffer.
Definition of diminished responsibility- The 'abnormality of mind' Section 2 of the Homocide Act 1957 states:
A person who kills is not to be convicted of murder if the defendant was suffering from an abnormality of mental functioning which:
- Arose from a recognised medical condition
- Substantially impaired the defendants ability to do one of the following: Understand the nature of his conduct, Form of rational judgement and exercise self-control.
- Provides an explanation for the defendants acts and omissions in doing the killing or being a party to the killing.
An abnormality of mental functioning which arose from a recognised medical condition
Under 1957 Homocide Act 'abnormality of the mind has been held to cover many different kinds of medical conditions, such as psychotic disorders BYRNE- A sexual psychopath's inability to control his perverted desires meant he could plead diminished responsibility. It can also be as a result of post-natal depression, a young mother killed her mother with a hammer.
The Homocide Act 1957 required that a person's mental responsibility must be substantially impaired, but did not specify in which way so the Coroners and Justice Act 2009 attempts to clarify this.
It must be shown that the abnormality of mental functioning substantially impaired the defendants ability to understand…