(11) For the purposes of this regulation, “authorised person” means—  12. —(1) A constable may enter premises in order—  (2) The power in paragraph (1) is exercisable if the constable—  (3) A constable exercising the power in paragraph (1)—  (4) A constable exercising the power in paragraph (1)—  (5) In this regulation, “premises” includes any building or structure and any land.  13. —(1) Subject to the following provisions of this regulation, an operator must ensure that a  passenger who arrives at a port in England on a relevant service is provided with the information  required by regulation 14 (“the passenger information requirement”) and in the manner required  by that regulation at each of the times specified in paragraph (2).  (2) The times are—  (a) a constable;  (b) for the purposes of paragraphs (2) and (3) only, an immigration officer; or  (c) a person designated by the Secretary of State for the purposes of this regulation.  (a) to search for a person who is suspected of committing an offence of contravening the  requirement in paragraph 10 (duty to self-isolate) of Schedule 11;  (b) to remove a person of the description in sub-paragraph (a) to accommodation designated  by the Secretary of State for the purposes of Schedule 11.  (a) has reasonable grounds to believe that a person of the description in paragraph (1)(a) is in  or on the premises; and  (b) has a reasonable belief that it is necessary and proportionate to enter the premises for the  purposes specified in paragraph (1)(b).  (a) may use reasonable force if necessary; and  (b) may be accompanied by a police community support officer.  (a) if asked by a person on the premises, must show evidence of the constable’s identity and  outline the purpose for which the power is being exercised; and  (b) if the premises are unoccupied or the occupier is temporarily absent, must leave the  premises as effectively secured against unauthorised entry as when the constable found  them.  PART 4  Requirements on operators  Passenger information requirement  Power of entry  (a) where prior to departure a booking was made for the passenger to travel on the relevant  service, before the booking was made (“the pre-booking information requirement”);  (b) where, at least 48 hours prior to the scheduled departure time of the relevant service, a  booking was made for the passenger to travel on it, between 24 and 48 hours prior to the  scheduled departure time of that service (“the pre-departure information requirement”);  (c) where prior to departure the passenger was checked in to travel on the relevant service, at  the time of check-in (“the check-in information requirement”); and  (d) while the passenger was on board the vessel, aircraft or train (“the on-board information  requirement”).  19