DPP v Dukolli

Where an accused relies on post-driving alcohol consumption to displace the statutory assumption concerning a breathalyser reading, the accused must prove both the post-driving consumption and that, without it, the alcohol level would have been below the prescribed limit. Expert medical or scientific evidence will ordinarily be required where the causal effect of the later consumption is not obvious to a lay person. Magistrates retain a discretion to decide the issue without such evidence, but only in the comparatively rare case where a lay person can reliably and confidently conclude that the later alcohol must explain the excess.

The Director of Public Prosecutions appealed by case stated from the respondent’s acquittal by York Magistrates’ Court on a charge under section 51A of the Road Traffic Act 1998. The respondent accepted that he had consumed alcohol after stopping the vehicle, but the magistrates concluded that this later consumption had caused his breath alcohol level to exceed the prescribed limit. The central issues were whether the statutory assumption under section 15 of the Road Traffic Offenders Act 1988 could be displaced without scientific evidence and whether the magistrates’ conclusion was reasonably open to them.

1. Appeal allowed. The magistrates’ acquittal was set aside and the case was returned with a direction to convict.

2. Section 15(2) of the Road Traffic Offenders Act 1988 creates an assumption that the proportion of alcohol was at least that revealed by the breath specimen. Under section 15(3), the accused bears the burden of proving on the balance of probabilities that: (i) alcohol was consumed after driving ceased; (ii) that consumption caused the level to exceed the prescribed limit; and (iii) without it, the level while driving would have been below the limit.

3. The authorities, including Dawson v Lunn, Pugsley v Hunter, DPP v Singh and DPP v Bolton, established that medical or scientific evidence will normally be necessary where the causal effect of the later alcohol consumption is not obvious to a lay person. The purpose is both to test whether the alleged consumption could account for the reading and to assist in assessing the reliability of the account.

4. Magistrates may decide the issue without expert evidence in the comparatively rare case where a lay person can reliably and confidently conclude that the later alcohol must explain the excess. This was not such a case. The respondent’s account conflicted with his earlier statements, and it was not obvious that a mouthful of vodka could explain the recorded reading. No reasonable bench could therefore conclude that the statutory assumption had been displaced.

5. Lord Justice Elias agreed that the evidence concerning alcohol consumed before and after driving could not be separated and that expert evidence was required to evaluate the alleged post-driving consumption and its effect on credibility.

• High Court (Administrative Court): On an appeal by case stated, the court held that the magistrates had erred in finding that the statutory assumption was displaced and directed them to convict.
• York Magistrates’ Court: The respondent was acquitted on 18 September 2008.