6Provisions as to clearance
(1)For the purpose of securing compliance with the provisions of this Act or any order made under section one of this Act or with any other enactment relating to the importation or exportation of goods or with the law relating to trading with the enemy—
(a)an officer of Customs and Excise may at any time refuse clearance to any ship, and
(b)where clearance has been granted to a ship, an officer of Customs and Excise, an officer of His Majesty's Navy, or any person authorised in that behalf by the Commissioners of Customs and Excise may, at any time whilst the ship is within the limits of a port in the United Kingdom, demand that the clearance shall be returned to the person making the demand.
(2)Any such demand may be made orally on the master of the ship or by serving a written demand in any manner authorised by section six hundred and ninety-six of the [57 & 58 Vict. c. 60.] Merchant Shipping Act, 1894, for the service of documents which are, under that Act, to be served on the master of a ship.
(3)Where a demand is so made for the return of a clearance—
(a)the clearance shall forthwith become void, and
(b)if the demand is not complied with, the master of the ship shall be liable to a customs penalty of one hundred pounds.
(4)This section shall apply to aircraft, as if references in this section and in section six hundred and ninety-six of the Merchant Shipping Act, 1894, to a ship, the master of a ship, and a port included respectively references to an aircraft, the pilot of an aircraft and an aerodrome.