(1)Subject to subsection (2) of this section, the following murders shall be capital murders, that is to say.—
(a)any murder done in the course or furtherance of theft;
(b)any murder by shooting or by causing an explosion; 2
(c)any murder done in the course or for the purpose of resisting or avoiding or preventing a lawful arrest, or of effecting or assisting an escape or rescue from legal custody,
(d)any murder of a police officer acting in the execution of his duty or of a person assisting a police officer so acting;
(e)in the case of a person who was a prisoner at the time when he did or was a party to the murder, any murder of a prison officer acting in the execution of his duty or of a person assisting a prison officer so acting.
(2)If, in the case of any murder falling within the foregoing subsection, two or more persons are guilty of the murder, it shall be capital murder in the case of any of them who by his own act caused the death of, or inflicted or attempted to inflict grievous bodily harm on, the person murdered, or who himself used force on that person in the course or furtherance of an attack on him; but the murder shall not be capital murder in the case of any other of the persons guilty of it.
(3)Where it is alleged that a person accused of murder is guilty of capital murder, the offence shall be charged as capital murder in the indictment, and if a person charged with capital murder is convicted thereof, he shall be liable to the same punishment for the murder as heretofore.
(4)In this Act " capital murder " means capital murder within subsections (1) and (2) of this section.
(5)In this section—
(a)" police officer " means a constable who is a member of a police force or a special constable appointed under any Act of Parliament, and " police force " has the same meaning as in section thirty of the Police Pensions Act, 1921 (as amended by the Police Act, 1946) or, as regards Scotland, the same meaning as in section forty of the Police (Scotland) Act, 1956;
(b)" prison " means any institution for which rules may be made under the Prison Act, 1952, or the Prisons (Scotland) Act, 1952, and any establishment under the control of the Admiralty or the Secretary of State where persons may be required to serve sentences of imprisonment or detention passed under the Naval Discipline Act, the Army Act, 1955, or the Air Force Act, 1955;
(c)" prison officer " includes any member of the staff of a prison;
(d)" prisoner " means a person who is undergoing imprison" ment or detention in a prison, whether under sentence or not, or who, while liable to imprisonment or detention in a prison, is unlawfully at large;
(e)" theft " includes any offence which involves stealing or is done with intent to steal.