Scheiner v Director of Public Prosecutions

A breath analysis is not invalid merely because a mobile telephone or police radio may have been present and switched on contrary to a manufacturer’s recommendation. The prosecution need not prove that interference was impossible. The relevant question is whether evidence raises a realistic possibility that the device malfunctioned and produced a false reading. A breath test remains valid where the approved device was used, the operator acted bona fide, and the result is reliable on the evidence. Mere non-compliance with a manufacturer’s recommendation, without evidence of impairment or inaccuracy, is insufficient.

The claimant was convicted by the Brent Magistrates’ Court after an evidential breath test showed alcohol above the prescribed limit. The Crown Court dismissed his appeal, accepting expert evidence that there was no evidence that the result was inaccurate. The claimant appealed to the Divisional Court, arguing that the test was invalid because the operator probably had a switched-on mobile telephone with him, contrary to the manufacturer’s instructions. The central issue was whether that possible breach necessarily prevented the analysis from being a valid breath test.

1. Appeal dismissed. The Crown Court had not erred in law.
2. Under DPP v Carey [1970] AC 1072, the statutory requirements are satisfied where an approved device is used and the constable conducts and evaluates the test bona fide. Instructions must be observed where, in the circumstances known to the operator, they are necessary to obtain a reliable indication. However, inadvertent or ignorant non-compliance does not invalidate the test where the operator acted bona fide and the test was administered for the statutory purpose.
3. The issue was therefore one of proof. Applying Cracknell v Willis [1988] RTR 1, there is a presumption that the machine is reliable, but relevant evidence may require the court to be satisfied that the particular reading can be relied upon.
4. The Crown Court was entitled, and indeed bound, to rely on the device because the evidence did not show that the possible presence of a switched-on mobile telephone impaired its operation. Evidence must at least raise a realistic possibility that the device malfunctioned and produced a false reading. A bare assertion that a manufacturer’s recommendation was not followed is insufficient.
5. The court stated that mere presence of a mobile telephone or police radio should not in future be treated as enough to make an Intoximeter EC/IR result inadmissible or unreliable. The stated question was answered in the negative.

• Brent Magistrates’ Court: convicted the claimant.
• Harrow Crown Court: dismissed the appeal against conviction.
• High Court (Administrative Court): dismissed the appeal and answered the stated question in the negative.