The Court of Appeal dismissed the Director of Public Prosecutions’ appeal in a case about whether a Garda could form the opinion needed to arrest a driver based solely on a positive roadside breath test.
The judgment, delivered by Mr Justice Patrick McCarthy on 18 November 2019, concerned Keenan McGovern, who was stopped at a checkpoint on 3 September 2016. The roadside alcometer returned a “Fail” but did not show the alcohol concentration or whether he exceeded a permitted limit. The judgment records that he drove to the checkpoint without difficulty and showed no signs of intoxication.
A later station breath test measured alcohol in his breath at 54 micrograms per 100 millilitres. The judgment says that result was sufficient to ground a conviction, but the evidence was excluded after the District Court deemed the arrest unlawful. The District Court then dismissed the prosecution.
The District Court judge had relied on a submission that the Supreme Court’s decision in DPP v Gilmore meant a roadside “Fail” alone could not support the Garda’s opinion. On a case stated, the High Court ruled against that interpretation. McGovern appealed, arguing that the matter involved a factual finding rather than a question of law.
The Court of Appeal said the District Court’s decision turned on an error of law about whether a positive roadside breath test could, by itself, support the Garda’s opinion. It cited the Supreme Court’s reasoning in Gilmore, which concerned analogous legislation and held that a positive breathalyser result could be sufficient to justify such an opinion.
Mr Justice McCarthy answered the legal question in the negative: a Garda’s opinion based solely on the roadside test result could be sufficient to found a reasonable opinion that a person was incapable of having proper control of a vehicle. The Court of Appeal accordingly dismissed McGovern’s appeal. The judgment did not itself determine the prosecution’s outcome after that ruling.