(1)Any officer authorised in accordance with this section to exercise the powers conferred by this subsection may (subject to that authority) call out the Ulster Defence Regiment or any part of it for emergency service in Northern Ireland if, and for so long as, it appears to that officer to be necessary or expedient for the defence of life or property in Northern Ireland against armed attack or sabotage, whether actual or apprehended.
(2)The Secretary of State may—
(a)grant authority in writing to any designated officer of the regular forces within the meaning of the [1955 c. 18.] Army Act 1955 of a rank not lower than major to exercise the powers conferred by subsection (1) above, and
(b)by that authority authorise that officer in turn to authorise any other officer designated by him (being an officer of the regular forces within the meaning of that Act of 1955 of a rank not lower than major) to exercise those powers,
and any authorisation in pursuance of this subsection may be given either in general terms or subject to specified limitations.