1

A person (“D”) who kills or is a party to the killing of another is not to be convicted of murder if D was suffering from an abnormality of mental functioning which—

a

arose from a recognised medical condition,

b

substantially impaired D's ability to do one or more of the things mentioned in subsection (1A), and

c

provides an explanation for D's acts and omissions in doing or being a party to the killing.

1A

Those things are—

a

to understand the nature of D's conduct;

b

to form a rational judgment;

c

to exercise self-control.

1B

For the purposes of subsection (1)(c), an abnormality of mental functioning provides an explanation for D's conduct if it causes, or is a significant contributory factor in causing, D to carry out that conduct.