Supreme Court: DPP succeeds in appeal against quashed drunk driving conviction

About this case:

• Citation:
  [2026] IESC 33
• Judgment:
  External link
• Court:
  Supreme Court
• Judge:
  Ms Justice Iseult O'Malley

Delivering judgment for the Supreme Court, Ms Justice Iseult O’ Malley opined: “The overall burden on the prosecution is to prove the guilt of the accused beyond reasonable doubt by means of admissible evidence. It is entirely well-established law that the burden does not include an obligation to exclude every hypothetical possibility of innocence, that “beyond reasonable doubt” does not mean mathematical certainty, and that relevant evidence is admissible unless excluded by an exclusionary rule or in an exercise of the judge’s discretion to exclude evidence on the basis that its prejudicial effect outweighs its probative value.”

Background

The respondent was arrested by Garda Houlihan on 20 August 2022, having failed to supply a breath specimen at a checkpoint.

He was conveyed to a garda station, where a blood sample was taken by a designated doctor. The doctor divided the specimen between two glass bottles which were placed into separate containers sealed with a numbered seal.

Both the doctor and Garda Houlihan followed the procedure prescribed by s.15 of the Road Traffic Act 2010. The garda completed the form required by s.15 of the Act, offered the respondent the option of taking one of the sealed containers, and put the remaining container and the form into a marked cardboard box, which was then sealed and forwarded to the Medical Bureau of Road Safety by post the following day.

In a prosecution for an offence under the Act, there is a presumption pursuant to s.15(4) thereof, until the contrary is shown, that those steps were taken. Under s.20 thereof, a certificate issued under s.17 shall, until the contrary is shown, be sufficient evidence in proceedings under the Act of the facts stated in it and of compliance by the Bureau with its statutory requirements.

On 29 August 2022, the Bureau issued a s.17 certificate of analysis in relation to the respondent’s sample recording a blood alcohol concentration exceeding the statutory limit.

The respondent was prosecuted in the District Court for drunk driving contrary to s.4(2) of the Act.

The defence challenged the s.17 certificate on the basis that Garda Houlihan had not provided evidence of the safekeeping of the package containing the specimen between the time it was taken and the time it was posted, allegedly rendering the evidence inadmissible on the basis that there was no evidence as to whether it had been stored somewhere that other persons might have had access to, relying on A. McD [2016] 3 I.R. 123.

The District Court determined that the prosecution was not obliged to tender such evidence and convicted the respondent.

The defence applied for judicial review to the High Court. Ms Justice Sara Phelan quashed the conviction, finding that there was a legal requirement to prove the chain of custody of the specimen and that there was a gap in the evidence not covered by the statutory presumptions of the Act.

Issues on appeal

The DPP brought a leapfrog appeal from the decision of the High Court, with the issues for the Supreme Court being:

• Whether there exists a legal requirement to prove the chain of custody for forensic samples, or whether it is a question of fact as to whether a forensically analysed sample is the same as that obtained from the suspect.
• Whether a ruling of law in the course of a criminal trial in the District Court can be subject to judicial review.

The Supreme Court

Ms Justice Iseult O’ Malley considered that the High Court’s analysis was based a number of propositions, including that the blood specimen was an item of real evidence, that the decision in A. McD required proof of a chain of custody in respect of real evidence in all cases and that real evidence is inadmissible if there is a gap in that evidence, that the statutory presumptions and certificate evidence did not dispense with the need to prove the chain of custody, and that the statutory procedures for the handling of specimens did not establish the integrity of the specimen.

Noting that each proposition was incorrect, the judge explained that firstly, specimens taken under the 2010 Act are not evidence “in any sense” as they are not produced in court.

Highlighting that the s.17 certificate constitutes the evidence that a driver was over the limit, the court noted that the content of the certificate is admissible “because the Act makes it admissible. Without that statutory foundation it would simply be inadmissible hearsay as if the analyst had simply written a letter describing the analysis and findings.”

Ms Justice O’ Malley continued: “The Act also sets out the criteria for the certificate’s admissibility – it must be on a prescribed form and must be “duly completed”. If these criteria are satisfied, the certificate is admissible and its contents become evidence.”

The judge opined that there is no general rule of law requiring evidence of a chain of custody for real evidence and emphasised that A. McD did not purport to lay down a general rule of law requiring proof of a chain of custody of physical objects as a condition of admissibility of evidence about them. 

In that regard, the court considered that the focus in A. McD was on the reliability and weight of CCTV footage, and that in referring to the chain of custody, the judgment “simply stated that the party adducing the evidence “must be able” to account for its custody, to exclude the possibility of tampering. This, however, is a matter for the finder of facts and not a condition of admissibility.”

As to the respondent’s submission that the “inextricable link” to the certificate meant that if the integrity of the specimen is not reliable, then the certificate should not be admitted, Ms Justice O‘ Malley considered that the submission failed to take account of the effect of the statutory provisions and conflated the concepts of reliability and admissibility, as any doubt as to the identity of the specimen be a sufficiency issue rather than an admissibility issue.

As to the contents of the s.15 form and the s.17 certificate, the court recounted the High Court’s concern that the Bureau was not asked in the form to indicate whether or not the container seal had been tampered with.

Ms Justice O’ Malley remarked that it was “unfortunate” that the High Court was not shown the kit, as it would have been obvious whether containers had been tampered with or replaced due to their serial numbers, and that this would prevent the Bureau from certifying that the specimen was “the” specimen to which the particulars related.

The judge considered that the Act makes practical arrangements for the safeguarding of the integrity of the specimen by allowing for evidence to be given by certificate and providing for presumptions of statutory compliance, and that it is open to the defence to raise any question of admissibility by reference to established exclusionary rules or as to reliability based on the prosecution evidence or evidence adduced by the defence themselves.

Ms Justice O’ Malley expressed her firm view that the case was not one for judicial review, finding that the focus was on the alleged error in the interpretation of the statute and that “Such an error does not necessarily mean that the judge has thereby exceeded their jurisdiction. It is a matter far more suited to a case stated on a point of law than to judicial review.”

Conclusion

Accordingly, the Supreme Court allowed the appeal.

Andrejs Ratinskis v Director of Public Prosecutions [2026] IESC 33