PART IIN.I.Homicide and suicide

5Effect, in cases of homicide, of impaired mental responsibility.N.I.

[F1(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 mental 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.

(1C)Where, but for this section, D would be liable, whether as principal or as accessory, to be convicted of murder, D is liable instead to be convicted of manslaughter.]

(2)Where a person is found guilty of manslaughter under [F2subsection (1C)], the powers of the court to make a hospital order[F3 Article 44 of the Mental Health (Northern Ireland) Order 1986 may be exercised as if the condition mentioned in paragraph (2)(a) of that Article were fully satisfied and as if in paragraph (7) of that Article the words “upon the evidence taken into account under that sub-paragraph” and the words from “and no such order” to the end were omitted; and where any such hospital order is made, the court shall make a restriction order under Article 47 in respect of that person], but nothing in this section shall restrict the powers of the court to sentence that person for the offence of manslaughter of which he is found guilty.

(3)On a charge of murder, it shall be for the defence to prove that the person charged is by virtue of this section not liable to be convicted of murder; but the prosecution, with the leave of the court, may assume the burden of such proof and proceed accordingly subject to any directions which may be given by the court as to the stage of the proceedings at which the prosecution may adduce or elicit evidence tending to such proof.

(4)Proof shall be sufficient to reduce, under this section, a verdict of murder to one of manslaughter if it satisfies the jury that, on the balance of probabilities, the accused was suffering from [F4abnormality of mental functioning] of the kind referred to in subsection (1).

(5)Where on a charge of murder the jury reject the plea that the person charged was an insane person, they may find him to be a person suffering from [F5abnormality of mental functioning] of the kind referred to in subsection (1).

(6)The fact that one party to a killing is by virtue of this section not liable to be convicted of murder shall not affect the question whether the killing amounted to murder in the case of any other party to it.