s 20A Exceeding alcohol limit for prescribed safety-critical duties
(1) A person subject to service law (“P”) commits an offence if the proportion of alcohol in P's breath, blood or urine exceeds the relevant limit at a time when P— (a) is performing, or purporting to perform, a prescribed duty; or (b) might reasonably expect to be called on to perform such a duty. (2) In subsection (1) “ prescribed duty ” means a duty specified, or of a description specified, by regulations; but a duty or description may be specified only if performing that duty (or a duty of that description) with ability impaired by alcohol would result in a risk of— (a) death; (b) serious injury to any person; (c) serious damage to property; or (d) serious environmental harm. (3) In this section “ the relevant limit ”, in relation to a duty specified or of a description specified by regulations, means the limit prescribed by regulations in relation to that duty or duties of that description. (4) In this section “ regulations ” means regulations made by the Defence Council for the purposes of this section. (5) A person guilty of an offence under this section is liable to any punishment mentioned in the Table in section 164, but any sentence of imprisonment imposed in respect of the offence must not exceed two years.