(1)Subject to subsections (2) and (3), in relation to a person who is subject to service law or a vehicle in the charge of such a person, the powers conferred on a service policeman by section 2 may also be exercised—
(a)by that person’s commanding officer, or
(b)by any member of Her Majesty’s forces who is authorised by that person’s commanding officer.
(2)The power conferred on a commanding officer by virtue of subsection (1)(a) may be exercised only by giving orders for the search of a particular person or vehicle.
(3)A commanding officer may not give orders by virtue of subsection (1)(a) or give authority under subsection (1)(b) unless he has reasonable grounds for believing that it is likely that, if the powers conferred by section 2 could not be exercised before the earliest time by which it would be practicable to obtain—
(a)the assistance of a service policeman, or
(b)in a case where corresponding powers conferred by section 1 of the 1984 Act or any other enactment are exercisable by a member of a United Kingdom police force, the assistance of a member of such a force who is capable of exercising those corresponding powers,
offences against section 70 of either of the 1955 Acts or section 42 of the 1957 Act would be committed or persons who have committed such offences would avoid apprehension.