Supreme Court ruling ends drink-driving doubts
A recent Supreme Court decision has ended almost a year of doubt and delay surrounding drink-driving and drug-driving prosecutions involving the taking of a specimen, attendees at a Dublin Solicitors Bar Association (DSBA) webinar heard.
The decision (11 June) concerned the case of Ratinskis v Director of Public Prosecutions, which hinged on the provision of evidence regarding the chain of custody for blood samples.
Systemic importance
“Because this case was considered to be of systemic importance and prosecutions were being adjourned across the board, the Supreme Court granted permission to take it on directly, effectively sidestepping the Court of Appeal,” barrister Martin Dully told the DSBA Road Traffic Law Updates webinar (17 June).
The background of the case is that on 20 August 2022, the respondent, Andrejs Ratinskis, was arrested at a mandatory checkpoint, having failed to provide a breath specimen.
A blood sample was taken at the garda station at 12.37am and divided, as normal, into two sealed, numbered containers.
One container was given to the respondent; the other was posted to the Medical Bureau of Road Safety (MBRS) on 22 August.
It issued a section 17 certificate on 29 August showing a blood-alcohol concentration of 126mg/100ml, and Ratinskis was subsequently prosecuted in the District Court.
“The defence submitted that the sample results were inadmissible in evidence because the prosecution had produced no evidence at all as to the manner in which this specimen had been stored after it had been taken and prior to its posting to the MBRS,” said barrister Martin Dully during the DSBA update on 17 June.
“The point raised here is that there's an obligation on the prosecution to prove what is commonly referred to as chain of custody to rule out even the mere suggestion or possibility of some form of interference with the integrity of the specimen.
“Unsurprisingly, this didn't enjoy too much favour from the District Court judge who ultimately convicted the accused.”
Judicial review
The accused then brought judicial-review proceedings in lieu of just simply appealing the matter to the Circuit Court or proceeding by way of case status.
This then led to “possibly one of the most surprising decisions in this area of the law”, in Dully’s experience.
In the High Court on 31 July 2025, Ms Justice Sara Phelan held that the statutory presumptions did not cover the period between sealing the sample and its transmission to the MBRS and that the prosecution was required to adduce chain-of-custody evidence to bridge that gap.
“Ultimately, she decided to quash the conviction on the basis that there had been no evidence regarding the chain of custody of the case and indicated that the court was left with no other legal option than to acquit the accused,” Dully explained.
“This caused consternation in terms of the prosecution of drink-driving cases and drug-driving cases, because it has never been the practice of the prosecution to produce any evidence relating to the chain of custody.
“Had this remained the law, it would have resulted in a situation where it would have been effectively impossible to ever prove sufficient chain of custody in any case to rule out the possibility of any potential interference with the specimen.
“Outside of Dublin certainly, all specimens are sent through the postal system, so it would be utterly impracticable for the prosecution to be ever in a position to prove what happened to a specimen and who had custody at any given time, while it remained in the postal system.”
Rejected
The defence case in the High Court rested on six propositions, all of which were ultimately rejected by the Supreme Court, Dully explained.
The first was the assertion that the specimen itself – be it of blood or urine – was what might be described as an item of real evidence.
The Supreme Court emphasised that the real evidence referred to the certificate rather than the specimen itself.
The second and very important finding of the Supreme Court was that there was no general rule of law in criminal evidence requiring absolute proof of a chain of custody for what might be described as real evidence.
“A failure to prove a chain of custody relating to the provision of a specimen does not necessarily render the certificate inadmissible,” said Dully.
“The Supreme Court went on to say that the burden on the prosecution in these cases does not actually require the exclusion of every hypothetical possibility in terms of interfering with the specimen.
“That's not what the Road Traffic Act 2010 requires,” Dully concluded.