51.—(1) A constable or a financial investigator may for the purposes of an investigation into[F1 drug trafficking] apply to a[F1 Crown Court] judge for a warrant under this Article in relation to specified premises.
(2) On such application the judge may issue a warrant authorising a constable to enter and search the premises if he is satisfied—
(a)that an order made under Article 50 in relation to material on the premises has not been complied with, or
(b)that the conditions in paragraph (3) are fulfilled, or
(c)that the conditions in paragraph (4) are fulfilled.
(3) The conditions referred to in paragraph (2)(b) are—
(a)that there are reasonable grounds for suspecting that a specified person[F1 has carried on drug trafficking]
(b)that the conditions in Article 50(4)(b) and (c) are fulfilled in relation to any material on the premises, and
(c)that it would not be appropriate to make an order under that Article in relation to the material because—
(i)it is not practicable to communicate with any person entitled to produce the material,
(ii)it is not practicable to communicate with any person entitled to grant access to the material or entitled to grant entry to the premises on which the material is situated, or
(iii)the investigation for the purpose of which the application is made might be seriously prejudiced unless a constable could secure immediate access to the material.
(4) The conditions referred to in paragraph (2)(c) are—
(a)that there are reasonable grounds for suspecting that a specified person[F1 has carried on drug trafficking]
(b)that there are reasonable grounds for suspecting that there is on the premises material relating—
(i)to the specified person, or
(ii)to[F1 drug trafficking]
which is likely to be of substantial value (whether by itself or together with other material) to the investigation for the purpose of which the application is made, but that the material cannot at the time of the application be particularised, and
(c)that—
(i)it is not practicable to communicate with any person entitled to grant entry to the premises; or
(ii)entry to the premises will not be granted unless a warrant is produced; or
(iii)the investigation for the purpose of which the application is made might be seriously prejudiced unless a constable arriving at the premises could secure immediate entry to them.
(5) Where a constable has entered premises in the execution of a warrant issued under this Article, he may seize and retain any material, other than items subject to legal privilege and excluded material, which is likely to be of substantial value (whether by itself or together with other material) to the investigation for the purpose of which the warrant was issued.