Subject to subsection (2) below, of any two specimens of breath provided by any person in pursuance of section 7 of this Act that with the lower proportion of alcohol in the breath shall be used and the other shall be disregarded.

If the specimen with the lower proportion of alcohol contains no more than 50 microgrammes of alcohol in 100 millilitres of breath, the person who provided it may claim that it should be replaced by such specimen as may be required under section 7(4) of this Act and, if he then provides such a specimen, neither specimen of breath shall be used.

If the person who makes a claim under subsection (2) above was required to provide specimens of breath under section 7 of this Act at or near a place mentioned in subsection (2)(c) of that section, a constable may arrest him without warrant.

F2Regulations may substitute another proportion of alcohol in the breath for that specified in subsection (2) above.