17(1)A person liable to be detained under paragraph 16 above may be arrested without warrant by a constable or by an immigration officer.
(2)If—
(a)a justice of the peace is by written information on oath satisfied that there is reasonable ground for suspecting that a person liable to be arrested under this paragraph is to be found on any premises ; or
(b)in Scotland, a sheriff, or a magistrate or justice of the peace, having jurisdiction in the place where the premises are situated is by evidence on oath so satisfied ;
he may grant a warrant authorising any constable acting for the police area in which the premises are situated, or in Northern Ireland any constable, at any time or times within one month from the date of the warrant to enter, if need be by force, the premises named in the warrant for the purpose of searching for and arresting that person.