Regulation 21

On the arrival of an infected ship or a suspected ship, or any other ship on which there has been, during its current voyage and within the last four weeks before arrival, a case of a disease subject to the International Health Regulations in respect of which the ship has not, outside the United Kingdom, been subjected to appropriate measures equivalent to those provided for in these regulations, the master shall take it to a mooring station unless an authorised officer otherwise allows or directs.

When the authorised officer has reason to believe that a ship on arrival may be one to which paragraph (1) of this regulation applies, he may direct the master to take it to a mooring station or to such other place as he considers desirable.