Sch 10 para 4
(1) If the officer carrying out a search of premises under paragraph 2 reasonably believes that it is necessary in order to carry out the search or to prevent it from being frustrated, he may— (a) require a person who is on the premises when the search begins, or who enters during the search, to remain on the premises; (b) require a person mentioned in paragraph (a) to remain in a specified part of the premises; (c) require a person mentioned in paragraph (a) to refrain from entering a specified part of the premises; (d) require a person mentioned in paragraph (a) to go from one specified part of the premises to another; (e) require a person who is not a resident of the premises to refrain from entering them. (2) A requirement imposed under this paragraph shall cease to have effect after the conclusion of the search in relation to which it was imposed. (3) Subject to sub-paragraph (4), no requirement under this paragraph for the purposes of a search shall be imposed or have effect after the end of the period of four hours beginning with the time when the first (or only) requirement is imposed in relation to the search. (4) An officer of the Royal Ulster Constabulary of at least the rank of superintendent may extend the period mentioned in sub-paragraph (3) in relation to a search by a further period of four hours if he reasonably believes that it is necessary to do so in order to carry out the search or to prevent it from being frustrated. (5) The power to extend a period conferred by sub-paragraph (4) may be exercised only once in relation to a particular search.