“A person whose leave to enter has been suspended under paragraph 2A may be detained under the authority of an immigration officer pending- (a) completion of his examination under that paragraph; and (b) a decision on whether to cancel his leave to enter. ”
“(3) Sub-paragraph 4 below applies where a person who is at large in the United Kingdom by virtue of this paragraph is subject to a restriction as to reporting to an immigration officer with a view to the conclusion of his examination under paragraph 2 or 2A above. (4) If the person fails at any time to comply with that restriction – (a) an immigration officer may direct that the person’s examination shall be treated as concluded at that time, but (b) nothing in paragraph 6 above shall require the notice giving or refusing him leave to enter the United Kingdom to be given within 24 hours of that time.”