Prevention of Oil Pollution Act 1971

7 Protection of acts done in exercise of certain powers of harbour authorities etc.

(1) Where any oil, or mixture containing oil, is discharged in consequence of—

(a) the exercise of any power conferred by sections 530 to 532 of the [1894, c. 60.] Merchant Shipping Act 1894 (which relate to the removal of wrecks by harbour, conservancy and lighthouse authorities); or

(b) the exercise, for the purpose of preventing an obstruction or danger to navigation, of any power to dispose of sunk, stranded or abandoned vessels which is exercisable by a harbour authority under any local enactment ;

and apart from this subsection the authority exercising the power, or a person employed by or acting on behalf of the authority, would be guilty of an offence under section 1 or section 2 of this Act in respect of that discharge, the authority or person shall not foe convicted of that offence unless it is shown that they or he failed to take such steps (if any) as were reasonable in the circumstances for preventing, stopping or reducing the discharge.

(2) Subsection (1) of this section shall apply to the exercise of any power conferred by section 13 of the [1865 c. 125.] Dockyard Ports Regulation Act 1865 (which relates to the removal of obstructions to dockyard ports) as it applies to the exercise of any such power as is mentioned in paragraph (a) of that subsection, and shall, as so applying, have effect as if references to the authority exercising the power were references to the Queen's harbour master for the port in question.