6.—(1) An enforcement officer may, if authorised, take possession of any article or substance found on relevant premises and retain it for as long as necessary—
(a)for it to be examined;
(b)for anything to be done to it which the enforcement officer may cause to be done under paragraph 5;
(c)to ensure that it is not tampered with before any examination or other procedure mentioned in paragraph (a) or (b) is complete;
(d)to ensure that it is available for use in any proceedings for an offence under these Regulations.
(2) The enforcement officer may exercise that power only if it appears to that officer that it is desirable to do so in the interests of security.
(3) Before taking possession of any substance under this paragraph, the enforcement officer must, if it is practicable—
(a)take a sample of it, and
(b)give a portion of the sample, marked so as to be identifiable, to a person in authority at the premises.
(4) An enforcement officer who takes possession of any article or substance under this paragraph must—
(a)if it is practicable to do so, give a notice to that effect to a person in authority at the premises;
(b)otherwise, fix such a notice in a conspicuous position at the premises.
(5) The notice must include sufficient information about the article or substance to identify it.