3(1)In order to perform functions under Part I or II of this Act an officer may require any person—
(a)to give details of any substances or articles on board a vessel, aircraft, hovercraft or marine structure ; and
(b)to give information concerning any substances or articles lost from a vessel, aircraft, hovercraft or marine structure.
(2)In order to perform any such functions an officer—
(a)may require any vessel, aircraft, hovercraft or marine structure to stop; and
(b)may require the attendance—
(i)of the master, captain or commander of a vessel, aircraft or hovercraft;
(ii)of the person in charge of a marine structure ; and
(iii)of any other person who is on board a vessel, aircraft, hovercraft or marine structure,
and may require any person on board to assist him in the performance of his functions.
(3)In order to perform functions under Part I of this Act an officer—
(a)may require—
(i)the master, captain or commander of a vessel, aircraft or hovercraft; and
(ii)the person in charge of a marine structure,
to take it and its crew to the port which appears to the officer to be the nearest convenient port; or
(b)may take it there himself.
(4)In order to perform any such functions an officer may detain a vessel, aircraft, hovercraft or marine structure.
(5)If an officer detains a vessel, aircraft, hovercraft or marine structure, he shall serve on the master, captain, commander or person in charge a notice in writing stating that it is to be detained until the notice is withdrawn by the service on him of a further notice in writing signed by an officer.