s 17 Warrants in England and Wales or Northern Ireland
(1) A justice of the peace may issue a warrant under this section if he is satisfied, on an application made by a constable, that the following conditions are met. (2) But an application for a warrant under subsection (1) may be made only in pursuance of a direction given under section 13. (3) The conditions are that— (a) criminal proceedings have been instituted against a person in a country outside the United Kingdom or a person has been arrested in the course of a criminal investigation carried on there, (b) the conduct constituting the offence which is the subject of the proceedings or investigation would (if it occurred in England and Wales or Northern Ireland ) constitute an indictable offence, or (if it occurred in Northern Ireland) constitute an arrestable offence , and (c) there are reasonable grounds for suspecting that there is on premises in England and Wales or (as the case may be) Northern Ireland occupied or controlled by that person evidence relating to the offence. “ Arrestable offence ” has the same meaning as in ... the Police and Criminal Evidence (Northern Ireland) Order 1989 ( S.I. 1989/ 1341 (N.I.12)). (4) A warrant under this section may authorise a constable— (a) to enter the premises in question and search the premises to the extent reasonably required for the purpose of discovering any evidence relating to the offence, (b) to seize and retain any evidence for which he is authorised to search.