The High Court ruled that a Garda could form the opinion needed to arrest a driver for a drink-driving offence based solely on a failed preliminary breath test, even though the device indicated only the presence of alcohol and did not measure its concentration.
Mr Justice McDermott delivered the judgment on 9 October 2018 in a case stated by District Judge Colin Daly. The question was whether the District Court judge was entitled to dismiss the prosecution after finding the respondent’s arrest unlawful. The High Court answered that question in the negative.
The respondent was stopped at a mandatory alcohol testing checkpoint at Quarryland, Kilkenny, on 3 September 2016. Garda Eamonn Long testified that the respondent’s driving drew no attention and that he showed no signs of intoxication. A Dräger Alcotest gave a “fail” result. Long said he formed the opinion that the respondent had consumed an intoxicant and committed an offence, and arrested him under section 4(8) of the Road Traffic Act 2010. The arrest was based solely on the preliminary test result.
At Kilkenny Garda Station, the respondent provided a further breath specimen. An Evidenzer IRL test recorded 54mg of alcohol per 100ml of breath, and a certificate was issued. He was charged with driving with a breath alcohol concentration above the statutory limit. The District Court judge accepted the defence submission that the failed preliminary test, which showed only the presence of alcohol, did not provide a reasonable basis for the Garda’s opinion. The judge found the arrest unlawful, treated the evidential specimen as unlawfully or unconstitutionally obtained and inadmissible, and dismissed the charge.
On the case stated, the High Court held that the threshold for forming the arrest opinion was low and that the Garda’s opinion could be based on the Dräger result alone. There was no suggestion that the Garda had acted in bad faith. The judgment said the device’s limits and the absence of other observations did not, on the facts presented, establish a legal basis for finding the opinion insufficient. It also stressed that the prosecution must prove the arrest lawful beyond reasonable doubt.
The ruling addressed the legal basis for the arrest and the District Court judge’s authority to make findings relevant to a legal ruling. It did not determine the respondent’s guilt or itself enter a conviction. The source records the answer to the stated question, but does not set out a separate order remitting the charge or what happened to the prosecution afterward.