21(1)A person liable to detention or detained under paragraph 16 above may, under the written authority of an immigration officer, be temporarily admitted to the United Kingdom without being detained or be released from detention; but this shall not prejudice a later exercise of the power to detain him.
(2)So long as a person is at large in the United Kingdom by virtue of this paragraph, he shall be subject to such restrictions as to residence [, as to his employment or occupation] and as to reporting to the police or an immigration officer as may from time to time be notified to him in writing by an immigration officer.
[(2A)The provisions that may be included in restrictions as to residence imposed under sub-paragraph (2) include provisions of such a description as may be prescribed by regulations made by the Secretary of State.
(2B)The regulations may, among other things, provide for the inclusion of provisions—
(a)prohibiting residence in one or more particular areas;
(b)requiring the person concerned to reside in accommodation provided under section 4 of the Immigration and Asylum Act 1999 and prohibiting him from being absent from that accommodation except in accordance with the restrictions imposed on him.
(2C)The regulations may provide that a particular description of provision may be imposed only for prescribed purposes.
(2D)The power to make regulations conferred by this paragraph is exercisable by statutory instrument and includes a power to make different provision for different cases.
(2E)But no regulations under this paragraph are to be made unless a draft of the regulations has been laid before Parliament and approved by a resolution of each House.]
[(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 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 under paragraph 2 above 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 twenty-four hours after that time.]