Sch 4A para 6
(1) A relevant officer may require a person found on the ship to produce a nationality document. (2) The relevant officer may search a person found on the ship where the officer has reasonable grounds to believe that a nationality document is concealed on the person. (3) The power conferred by sub-paragraph (2) may be exercised— (a) only if the officer has reasonable grounds to believe that a nationality document is concealed on the person; and (b) only to the extent that it is reasonably required for the purpose of discovering any such document. (4) Subject as follows, the officer may seize and retain a nationality document for as long as the officer believes the person to whom it relates will arrive in the United Kingdom by virtue of the exercise of the power in paragraph 2. (5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (6) A nationality document that has been seized and retained by a relevant officer must be passed to an immigration officer as soon as is practicable after the ship has arrived in the United Kingdom. (7) The power conferred by this paragraph to search a person does not authorise a relevant officer to— (a) require the person to remove any clothing in public other than an outer coat, jacket or gloves, or (b) seize and retain any document the officer has reasonable grounds to believe to be an item subject to legal privilege. (8) In this paragraph a “ nationality document ”, in relation to a person, means any document which might— (a) establish the person's identity, nationality or citizenship, or (b) indicate the place from which the person has travelled to the United Kingdom or to which the person is proposing to go. (9) A power conferred by this paragraph may be exercised on the ship or elsewhere.