—(1) In proceedings for an offence under section 67 or 68, evidence of the proportion of alcohol or of any drug or intoxicating substance in a specimen of breath or blood (as the case may be) provided by the accused shall be taken into account and, subject to subsection (2), it shall be assumed that the proportion of alcohol in the accused’s breath or blood at the time of the alleged offence was not less than in the specimen.
(2) Where the proceedings are for an offence under section 67(1)(a) or 68(1)(a) and it is alleged that, at the time of the offence, the accused was unfit to drive in that he was under the influence of drink, or for an offence under section 67(1)(b) or 68(1)(b), the assumption referred to in subsection (1) shall not be made if the accused proves —
that he consumed alcohol after he had ceased to drive, attempt to drive or be in charge of a motor vehicle on a road or any other public place and before he provided the specimen; and
that had he not done so the proportion of alcohol in his breath or blood —
(3) Subject to subsection (5) —
evidence of the proportion of alcohol in a specimen of breath may be given by the production of a document or documents purporting to be either a statement automatically produced by a prescribed breath alcohol analyser and a certificate signed by a police officer (which may but need not be contained in the same document as the statement) to the effect that the statement relates to a specimen provided by the accused at the date and time shown in the statement; and
evidence of the proportion of alcohol or of any drug or intoxicating substance in a specimen of blood may be given by the production of a document purporting to be a certificate signed by an authorised analyst as to the proportion of alcohol, drug or intoxicating substance found in a specimen of blood identified in the certificate.
(4) A specimen of blood shall be disregarded unless it was taken from the accused with his consent by a medical practitioner; but evidence that a specimen of blood was so taken may be given by the production of a document purporting to certify that fact and to be signed by a medical practitioner.
(5) A document purporting to be such a statement or such a certificate, or both, as is mentioned in subsection (3) is admissible in evidence on behalf of the prosecution in pursuance of this section only if a copy of it has been handed to the accused when the document was produced or has been served on him not later than 7 days before the hearing, and any other document is so admissible only if a copy of it has been served on the accused not later than 7 days before the hearing.
(6) A document purporting to be a certificate (or so much of a document as purports to be a certificate) is not so admissible if the accused, not later than 3 days before the hearing or within such further time as the court may in special circumstances allow, has served notice on the prosecution requiring the attendance at the hearing of the person by whom the document purports to be signed.
(7) A copy of a certificate required by this section to be served on the accused or a notice required by this section to be served on the prosecution may be served personally or sent by registered post.