The K-Zone: diminished responsibility

The defence of dimished responsibility is only available to a charge of murder and, if successful, reduces the conviction to manslaughter. This defence is widely used because murder has a mandatory life sentence. To succeed, the defendant must show that, on the balance of probability, the elements of dimished responsibility are in place. These are defined in s.2 of the HomicideAct1957:

at the time of the killing the defendant was suffering an `abnormality of mind', and
the abnormality led to the fatal act, and
the abnormality was such as to substantially reduce the ability of the defendant to take responsibility for his actions.

In practice it is necessary to get medical evidence in support of such a claim. Even then the prosecution may seek a ruling of insanity rather than dimished responsibility because, even though a defendent who is discharged by reason of insanity is not convicted of anything, he can be ordered to be detained for psychiatric treatment. A successful plea of diminished responsibility could result in a short prison sentence, followed by unsupervised release.

That diminished responsibility exists at all as a defence is probably because murder carried a mandatory death penalty until 1963.

CriminalLaw