Prosecution Appeals and the “Interests-of-Justice” Threshold After Jury Acquittal – Director of Public Prosecutions v JS [2025] IESC 32

Introduction

Case reference: The People (DPP) v JS, Supreme Court of Ireland, [2025] IESC 32, 11 July 2025.

The judgment addresses the scope of the prosecution’s “with-prejudice” right of appeal under s.23 of the Criminal Procedure Act 2010 (“CPA 2010”) following a jury acquittal where:

Evidence was excluded at trial on the basis that it was more prejudicial than probative;
The trial nonetheless proceeded and resulted in an acquittal.

The Court had to decide three principal issues:

Whether a prosecution appeal on a point of law lies against such an acquittal (the jurisdiction question);
Whether the trial judge erred in excluding the evidence (the error question); and
Whether, even if an error occurred, it is “in the interests of justice” to quash the acquittal and order a retrial (the retrial question).

Ultimately, the Court (O’Malley J. delivering the opinion; O’Donnell C.J., O’Malley, Woulfe, Hogan & Murray JJ. concurring) held that:

A point-of-law appeal is available to the prosecution in these circumstances;
The evidence was indeed erroneously excluded and met the statutory definition of “compelling evidence” in s.23(14);
However, the Director of Public Prosecutions (“DPP”) failed to show that a retrial was required “in the interests of justice”, so the acquittal was affirmed.

Summary of the Judgment

JS had accepted delivery of a postal package containing €6,000 worth of methamphetamine addressed to a house-mate. He had earlier pleaded guilty to cannabis and amphetamine supply charges arising from drugs found in his bedroom during the same search. At trial, the judge excluded any reference to those earlier guilty pleas and the related items, deeming them unduly prejudicial. The case went to the jury, which acquitted JS on the two remaining counts.

The DPP appealed under s.23 CPA 2010. The Court of Appeal found the exclusion erroneous, quashed the acquittal and ordered a retrial. JS obtained leave to the Supreme Court.

The Supreme Court held:

Section 23 permits a prosecution appeal on a point of law even when the impugned ruling involves an exercise of discretion (such as weighing probative value versus prejudice).
The trial judge’s analysis of the evidence’s probative value was inadequate; evidence of the contemporaneous drug dealing paraphernalia and guilty pleas was relevant to JS’s knowledge and intent and should have been admitted.
Notwithstanding that error, a retrial is not automatic. Where the original prosecution case remained viable and a jury has deliberated and acquitted, the DPP bears a heavy onus to justify disturbing the verdict. Absent a clear public-interest factor (e.g. extreme gravity, identifiable victim, systemic importance), a retrial will not be “in the interests of justice”. On the facts (value well below s.15A threshold, no victim, routine drug case, appellant already sentenced on related counts), the Court reinstated the acquittal.

Analysis

a) Precedents Cited

People (DPP) v JC [2017] 1 IR 417 – confirmed that s.23 allows prosecution appeals on any point of law available to a defendant.
People (DPP) v Meleady (No 3) [2001] 4 IR 16 – source of the probative/prejudice discretion.
People (DPP) v Almasi [2020] IESC 35 – Charleton J. clarified “marked prejudice” and the necessity of a balancing exercise.
People (DPP) v TN [2020] IESC 53 & People (DPP) v A McD [2016] IESC 71 – first major explorations of the two-stage test under s.23 (error + interests-of-justice).
People (DPP) v JB & SM [2025] IESC 10 – applied the s.23(11)/(12) factors recently and emphasised the DPP’s burden.
AG v Joyce & Walsh [1929] IR 256 – classic statement that misconduct evidence may be admissible if relevant to issues such as intention or accident.
English authorities on prosecution appeals and probative/prejudice (R v B [2008] EWCA Crim 1144; Criminal Justice Act 2003 ss.58-67) were referenced for comparative guidance.

b) Legal Reasoning

Admissibility as a Point of Law. A judge’s misuse of the probative/prejudice discretion is reviewable because the discretion is grounded in legal principles—failure to apply those principles or to assess relevant factors constitutes an error of law.
The Erroneous Exclusion. The evidence of guilty pleas, drugs, cash & paraphernalia was contemporaneous and probative of JS’s mens rea (knowledge of contents, intent to sell or joint enterprise). Its prejudicial effect, while real, did not outweigh its probative force. Hence exclusion was legally wrong.
Definition of “Compelling Evidence”. Reliability was unquestioned (formal pleas, seized items). Probative value was significant; when combined with existing evidence, a jury could feasibly convict – satisfying s.23(14).
Interests-of-Justice Test for Retrial. O’Malley J. analysed four considerations in s.23(12): fairness of future trial, lapse of time, victim’s interests, and “any other matter”. She highlighted:

The case was five-plus years old but still triable.
No identifiable victim existed.
The quantity/value of drugs rendered the case “routine”, below the s.15A threshold; appellant had already been punished for related offences.
The systemic significance of correcting the error was satisfied by the appellate clarification itself; a retrial would add little.

Policy Logic. Routine appeals whenever evidence is excluded would erode finality and burden courts. Section 23 aims to correct miscarriages of justice, not to offer the prosecution a “second bite” whenever a trial judge rules against them.

c) Impact of the Decision

Clarifies scope of prosecution appeals: Exclusion-of-evidence rulings are appealable points of law, but success on that ground does not guarantee a retrial.
Elevates the “interests-of-justice” hurdle: Where a full jury trial took place and the Crown had a viable case, retrial will be exceptional. The DPP must identify a compelling public-interest factor—mere evidential strengthening is insufficient.
Guidance for trial judges: Reasons for excluding evidence must explicitly engage with both probative value and prejudice. Failure to articulate that analysis risks reversal.
Practical effect on drug prosecutions: Evidence of contemporaneous drug-dealing paraphernalia may be admissible to prove intent, but appellate courts will scrutinise whether its exclusion, if erroneous, justifies rehearing.
Systemic balance: The decision preserves the Legislature’s intention to allow correction of legal errors while protecting the centuries-old principle of the finality of jury acquittals unless true interests-of-justice imperatives arise.

Complex Concepts Simplified

“With-prejudice” appeal: If the DPP wins, the original acquittal may be quashed and the accused retried (as opposed to a “without-prejudice” appeal, which only settles the law for future cases).
Probative vs. Prejudicial Evidence: “Probative” helps prove something important; “prejudicial” may unfairly sway the jury. Judges balance these factors to protect fairness.
Compelling Evidence (s.23(14)): Evidence that is reliable, substantially probative, and could reasonably lead a jury to convict when combined with the rest of the case.
Interests-of-Justice Test: Even when an error is found, the court must consider fairness of retrial, delay, victims, and other circumstances before setting aside an acquittal.
Section 23 CPA 2010: Irish statutory gateway granting the prosecution limited rights to appeal acquittals on points of law where evidence was wrongly excluded or a directed verdict was wrong.

Conclusion

DPP v JS is now the leading Irish authority on when a prosecution, having succeeded on an evidential point of law, is nevertheless not entitled to a retrial. It confirms that:

Discretionary evidentiary rulings are appealable points of law for the prosecution;
Exclusion of contemporaneous drug-dealing evidence here was erroneous, refining trial-level guidance on probative/prejudice analysis;
Yet, retrial is an exceptional remedy. Where a full jury has spoken and the case is routine in gravity, the DPP must demonstrate a distinct public-interest justification to overturn the acquittal.

The decision recalibrates the equilibrium between correcting legal error and respecting jury finality, ensuring that section 23 remains a targeted tool rather than an everyday prosecutorial option.