Sch 3 para 24
(1) In any proceedings for an offence under this Act, where the proceedings relate to a substance or article of which a sample has been obtained as mentioned in paragraph 1 of this Schedule, the part of the sample retained in pursuance of paragraph 10(a) of this Schedule shall be produced as evidence; and the court— (a) at the request of either party to the proceedings shall, and (b) in the absence of any such request may if it thinks fit, cause that part of the sample to be sent for analysis to the Government Chemist (or, in Northern Ireland, the Government Chemist for Northern Ireland) or to be sent for other appropriate examination to the person having the management or control of a laboratory specified by the court. (2) If, in a case where an appeal is brought, no action has been taken under the preceding sub-paragraph, the provisions of that sub-paragraph shall have effect in relation to the court by which the appeal is heard. (3) A person to whom a part of a sample is sent under this paragraph for analysis or other examination shall analyse or examine it, or cause it to be analysed or examined on his behalf, and shall transmit to the court a certificate specifying the result of the analysis or examination. (4) Any such certificate shall be signed by that person, or signed on his behalf by the person who made the analysis or examination or a person under whose direction it was made. (5) Any such certificate shall be evidence (and, in Scotland, shall be sufficient evidence) of the facts stated in the certificate unless any party to the proceedings requires that the person by whom it was signed shall be called as a witness; and, in any proceedings in Scotland, if that person is called as a witness, his evidence shall be sufficient evidence of those facts.