O'Sullivan v Director of Public Prosecutions

In deciding whether breath specimens were affected by mouth alcohol, the court must assess the evidence as a whole. It need not find that mouth alcohol was impossible, or rely on any single factor that conclusively excluded it. Evidence from a roadside test, the closeness of duplicate readings, later test results and the defendant’s evidence may be considered together. A later, non-statutory breath test may have probative value to rebut an allegation of mouth alcohol, although it cannot substitute for the statutory procedure used to prove the offence. Its admission remains subject to the court’s discretion under section 78 of the Police and Criminal Evidence Act 1984.

The claimant appealed by way of case stated from the Crown Court’s dismissal of his appeal against conviction by the magistrates’ court for driving with excess alcohol contrary to section 5 of the Road Traffic Act 1988.

Two evidential breath specimens produced readings of 71 and 73 micrograms of alcohol per 100 millilitres of breath. The claimant argued that mouth alcohol caused by regurgitation might have affected the readings. The Crown Court rejected that contention, relying on the roadside test, the closeness of the readings, a later Quick Test result and the evidence concerning the claimant’s medical condition. The central questions were whether that conclusion was Wednesbury unreasonable and whether the Quick Test result was legally admissible and relevant.

The appeal was dismissed. The court answered “No” to the question whether it was Wednesbury unreasonable for the Crown Court to conclude that mouth alcohol had not caused the excessive readings, and “Yes” to the question whether the Quick Test result could be taken into account.

1. Assessment of mouth-alcohol evidence. The Crown Court was entitled to consider the positive roadside test, particularly because the claimant had been asked whether he had consumed alcohol within the preceding 20 minutes and had answered no. It was for the Crown Court to determine the weight of that evidence.
2. The Crown Court was entitled to prefer the reasoning of Dr Mundy, whose evidence explained why readings of 71 and 73 would make repeated regurgitation at similar concentrations and intervals unlikely. The fact that an event was unlikely did not mean that it had to be shown to be impossible. The issue was whether, on all the evidence, the court was sure that mouth alcohol had not affected the specimens.
3. Quick Test evidence. The Quick Test was not relied upon to prove the statutory readings or as a substitute for the procedure prescribed by section 5 of the Road Traffic Act 1988. It was relevant to rebut the weakly supported suggestion that regurgitation had occurred. Its later timing gave it probative value for that limited purpose.
4. The absence of calibration did not make the evidence irrelevant in the circumstances. The device was said to be unreliable for detecting mouth alcohol, but the Crown Court was entitled to consider the result as part of the wider factual picture. There was also no unfairness in admitting it after the claimant had raised the issue. The Crown Court had considered the circumstances and exercised its discretion under section 78 of the Police and Criminal Evidence Act 1984, and that exercise was not shown to be defective.
5. The court did not need to decide the meaning of “breath” under section 5. It stated, obiter, that if the issue had arisen, it would have followed Zafar v Director of Public Prosecutions, holding that the decision was correct. The disqualification was not reduced to reflect delay.

High Court (Administrative Court): dismissed the case-stated appeal from the Crown Court’s dismissal of the claimant’s appeal against conviction by the Watford Magistrates’ Court.