Peer-Consent (“Romeo and Juliet”) Defence Requires Complainant’s Actual Attainment of 15: No Constitutional Right to a “Reasonable Mistake as to 15” Extension

Luke v Director of Public Prosecutions and Ors (High Court, Simons J), [2026] IEHC 182, 27 March 2026

Table of Contents

• 1. Introduction
• 2. Summary of the Judgment
• 3. Analysis
  • 3.1 Precedents Cited and Their Role
  • 3.2 Legal Reasoning
  • 3.3 Impact
• 4. Complex Concepts Simplified
• 5. Conclusion

1. Introduction

This judicial review challenged the constitutional validity of aspects of the “defilement” regime in s.3 of the Criminal Law (Sexual Offences) Act 2006 (as amended), focusing on the scope of the s.3(8) “peer consent” (or “Romeo and Juliet”) defence. The defence may apply where the complainant is 15 or 16, the accused is younger or less than two years older, and there is no authority/intimidatory/exploitative relationship.

The Accused argued that where he reasonably but mistakenly believed the complainant had reached 15, the Constitution required that the peer-consent defence be available. He advanced two constitutional lines:

• Mens rea / culpability: criminal liability for a serious offence cannot arise without a “core of criminal culpability”; excluding a “reasonable mistake as to 15” defence was said to criminalise the “mentally innocent”.
• Equality (Article 40.1): it was said to be unconstitutional to allow a defence where the complainant is in fact 15+, but deny it where the accused reasonably believed the complainant was 15+ but she was actually 14.

The court emphasised reporting restrictions protecting both parties’ anonymity, and that the judgment concerned constitutionality only, not the merits of the prosecution.

2. Summary of the Judgment

• Interpretation premise accepted: following Oscar v. Director of Public Prosecutions [2025] IECA 278 (affirming Oscar v. Director of Public Prosecutions [2024] IEHC 279), s.3(8) does not include an implied defence of reasonable mistake that the complainant had attained 15.
• Mens rea challenge rejected: s.3 overall retains mens rea safeguards because s.3(3) provides a defence where the accused proves reasonable mistake that the complainant had reached 17. Unlike the absolute-liability regime struck down in C.C. v. Ireland (No. 2) [2006] IESC 33, [2006] 4 IR 1, mens rea is not “wholly abrogated”.
• Equality challenge rejected: the s.3(8) age threshold (15) is a rational proxy for capacity to give legally effective consent within the peer-consent carve-out; extending the defence by reference to an accused’s belief about the complainant’s age would undermine the legislative design, including the coherence of requiring “consent”. The distinction therefore passes the Article 40.1 rationality test as described in Donnelly v. Minister for Social Protection [2022] IESC 31, [2023] 2 IR 415.
• Relief: judicial review dismissed.
• Costs (provisional): despite respondents’ success, the judge provisionally indicated no order as to costs against the applicant, noting the Legal Aid (Custody Issues) Scheme and public-interest clarification (with reference to S.O'C. v. Director of Public Prosecutions [2024] IECA 38).

3. Analysis

3.1 Precedents Cited and Their Role

Interpretation of s.3(8): no “reasonable mistake as to 15”

• Oscar v. Director of Public Prosecutions [2025] IECA 278 and Oscar v. Director of Public Prosecutions [2024] IEHC 279: These decisions fixed the interpretive baseline: s.3(8) is available only if the complainant in fact is 15–16. Simons J treated this as agreed and determinative of the statutory meaning, thereby concentrating this case on constitutionality rather than construction.
• C.C. v. Ireland (No. 1) [2005] IESC 48, [2006] 4 IR 1: Cited for the interpretive maxim expressio unius est exclusio alterius, supporting the conclusion that where the Oireachtas expressly included a reasonable-mistake defence in one provision but not another, that omission is deliberate and legally meaningful. Although used in Oscar to interpret s.3(8), its presence in this judgment underscores why the applicant could not “read in” a belief-based extension.
• C.C. v. Ireland (No. 2) [2006] IESC 33, [2006] 4 IR 1: Background driver of the 2006 Act: the Supreme Court struck down absolute liability for defilement under the 1935 Act because it criminalised the “mentally innocent” and provided “no way out”. The 2006 Act’s architecture (including mistake-of-age defences) was designed as a constitutional response.

Mens rea and “core culpability” after C.C.

• C.W. v. Minister for Justice and Equality [2023] IESC 22, [2024] 3 IR 554: Central to Simons J’s mens rea analysis. The Supreme Court reframed the ratio of C.C. (No. 2) as condemnation of the total abrogation of mens rea (“no way out”), not a general constitutional demand for maximal subjectivity in all elements. Simons J uses this to distinguish s.3: because s.3(3) provides a reasonable mistake defence as to attaining 17, s.3 does not replicate the unconstitutional “wholly abrogated” model.

Equality (Article 40.1): rationality standard for “pure” equality claims

• Donnelly v. Minister for Social Protection [2022] IESC 31, [2023] 2 IR 415: The judgment’s equality framework. Simons J applies the Donnelly propositions: presumption of constitutionality; challenger bears the burden; deference in social/moral policy; “pure” equality claims are assessed by rationality (arbitrariness/caprice/irrationality), not proportionality.
• Brennan v. Attorney General [1983] I.L.R.M. 449 and Dillane v. Ireland [1980] I.L.R.M. 167: These anchor the “legitimate purpose + relevance” formulation adopted in Donnelly and re-applied here.
• O'Meara v. Minister for Social Protection [2024] IESC 1, [2024] 1 I.L.R.M. 437: Used for the idea that internal inconsistency in a scheme can indicate arbitrariness. Simons J tests (and rejects) a suggested inconsistency between s.2 (under-15, reasonable mistake defence) and s.3(8) (peer-consent for 15–16 without mistake-of-15 allowance).
• Z.G. v. Ireland [2025] IESC 49: Used for two points: (i) age is a common and generally legitimate legislative classification, assessed by Donnelly rationality; (ii) age thresholds as proxies for maturity may be upheld even if “hard cases” exist at the margins.
• M. v. Ireland [2024] IEHC 523 and Brophy v. Director of Public Prosecutions [2026] IESC 7: Presented as illustrative bookends on age-based classification. M. struck down an arbitrary age-at-sentencing distinction for juvenile sentencing; Brophy upheld an age-at-trial distinction tied to vulnerability as a trial participant. Simons J uses them to show that the constitutionality of age lines turns on their connection to legislative purpose.
• O.R. (A minor) v. An tArd Chláraitheoir [2014] IESC 60, [2014] 3 IR 533: Cited for the necessity of identifying an appropriate comparator in equality analysis and ensuring comparators are “alike” for the relevant legal purpose.
• Re: The Illegal Immigrants (Trafficking) Bill 1999 [2000] 2 IR 360: Cited to reject the applicant’s argument that the second sentence of Article 40.1 is an exhaustive list of permissible differentiations. The case exemplifies justification by legitimate objective purpose independent of the affected persons’ “capacity” or “social function”.

Other cited authorities shaping context

• M.D. (A minor) v. Ireland [2012] IESC 10, [2012] 1 IR 697: emphasises judicial deference to legislative choices in framing sexual offences due to their “notorious difficulty” and social sensitivity.
• Galvin v. Director of Public Prosecutions [2025] IESC 35: initially raised as a prematurity objection to judicial review, later not pursued on clarified facts.
• People (Director of Public Prosecutions) v. P.B. [2025] IESC 12: cited on child-defendant anonymity under s.93 of the Children Act 2001.
• S.O'C. v. Director of Public Prosecutions [2024] IECA 38: relevant to costs where legal aid recommendations arise.
• K.U. v. Finland CE:ECHR:2008:1202JUD000287202, (2009) 48 E.H.R.R. 52 (noted in C.W.): referenced as recognising state obligations to criminalise/prosecute certain child-protection offences; also mention of Henchy J.’s dissent in Norris v. The Attorney General [1984] I.R. 36 on state obligations to protect children.

3.2 Legal Reasoning

(a) Statutory architecture: two distinct defences under s.3

The judgment draws a sharp line between:

• s.3(3): a full defence if the accused proves a reasonable mistake that the child had attained 17 (explicitly mental-state focused).
• s.3(8): a special peer-consent defence, available only where the complainant in fact has attained 15 but is under 17, with additional objective safeguards (age proximity; no authority; no intimidatory/exploitative relationship).

The court accepts that the Oireachtas intentionally created an objective gateway (actual attainment of 15) for the peer-consent carve-out, in contrast with the explicitly subjective s.3(3) defence.

(b) Mens rea: why C.C. (No. 2) does not constitutionalise a “mistake as to 15” defence

Simons J treats the applicant’s mens rea argument as attempting to “assimilate” his position to C.C. v. Ireland (No. 2). The assimilation fails because:

• In C.C. (No. 2) the vice was absolute liability for a grave offence with “absolutely no defence”—mens rea “wholly abrogated”.
• Under s.3 of the 2006 Act, there remains “a way out”: s.3(3) allows acquittal where the accused proves reasonable mistake as to 17. The offence, therefore, is not one where mental innocence is necessarily criminalised in the constitutional sense identified in C.W. v. Minister for Justice and Equality.
• The peer-consent defence is not the only safety valve; it is an additional, targeted carve-out for consensual peer activity premised on the complainant’s legal capacity to consent (set at 15, with safeguards).

(c) Equality: reframing the “difference in treatment” and applying Donnelly rationality

The applicant’s equality case was, in substance, a “pure” equality claim: he sought inclusion in a benefit (the s.3(8) defence) because he shared relevant similarity with those included (reasonable belief the other was 15+; small age gap).

The court’s key moves are:

• Comparator discipline (O.R. (A minor) v. An tArd Chláraitheoir): the applicant’s preferred comparison (focusing only on the accused’s moral culpability) was rejected as misdescribing what the scheme classifies. The scheme’s decisive classification is about the complainant’s legal capacity to consent, not the accused’s personal traits.
• Legitimate purpose: protecting children from sexual exploitation/inappropriate activity while permitting limited peer-consensual activity for older children; the purpose is constitutionally legitimate (also aligned with Article 42A and acknowledged in C.W.).
• Rational connection: using an age threshold (15) as a proxy for capacity is a classic legislative tool (Z.G. v. Ireland) and falls within the Oireachtas’s policy discretion, particularly in sensitive sexual-offence design (M.D. (A minor) v. Ireland).
• Coherence of “consent” within s.3(8): if s.3(8) were extended by reference to an accused’s belief that the complainant was 15, the statutory requirement that the complainant “consented” becomes incoherent where the complainant is in fact under 15, because the legislative scheme deems such a child incapable of legally effective consent. The court treats this as defeating, rather than supporting, the peer-consent carve-out’s purpose.
• No internal inconsistency (O'Meara): the presence of a reasonable-mistake defence under s.2 (under-15 offence) does not make it irrational to deny a belief-based extension under s.3(8); s.2 addresses a different (more serious) offence and different legislative calibration.

(d) Article 40.1 structure: the second sentence is not exhaustive

The applicant argued that unequal treatment is permitted only where justified by the second sentence of Article 40.1 (differences of capacity, physical/moral, or social function). The court rejects this as inconsistent with modern Supreme Court doctrine (notably Donnelly) and illustrates, via Re: The Illegal Immigrants (Trafficking) Bill 1999, that classifications may be justified by legitimate objective purposes beyond that enumerated phrasing.

(e) Procedure: judicial review vs plenary proceedings

Although the Supreme Court in Z.G. v. Ireland [2025] IESC 49 cautioned that direct primary-legislation validity challenges should generally proceed by plenary summons, Simons J declined to reopen/remit. The challenge was “tightly framed”, evidence needs were unclear, and delay would prejudice expedition of the underlying youth-involved prosecution.

3.3 Impact

• Confirms the narrowness of s.3(8): The “peer consent” defence is anchored to the complainant’s actual attainment of 15. Future attempts to “constitutionalise” a mistake-of-15 extension face a clear High Court rejection grounded in statutory coherence (capacity/consent) and Article 40.1 rationality.
• Stabilises the post-C.C. constitutional landscape: By emphasising C.W.’s reading of C.C. (No. 2), the judgment reinforces that the constitutional problem is not any strictness in child-protection offences per se, but the complete absence of any mens rea “way out” for serious offences.
• Clarifies “pure equality” limits in criminal-law benefits/defences: The decision illustrates that courts will not apply a proportionality-style “fairer alternative” inquiry to extend defences; challengers must show irrationality/arbitrariness under Donnelly, with significant deference in moral/social policy fields.
• Practical prosecutorial effect: Where the complainant is under 15, an accused close in age cannot rely on peer-consent by claiming a reasonable belief that she was 15; the relevant “mistake” safety valve remains the reasonable belief that she was 17 (s.3(3)) or, depending on charging, the different s.2 regime (which contains an explicit reasonable mistake defence as to 15 for that offence).

4. Complex Concepts Simplified

• Mens rea: the mental element of a crime (e.g., intention/knowledge/recklessness). The constitutional concern in C.C. (No. 2) was punishing someone for a serious offence with no meaningful mental-state escape.
• Absolute liability: liability without any mental element; if the prohibited act is proved, guilt follows, even for a person who acted blamelessly. This was central to C.C. (No. 2).
• Reasonable mistake as to age: a defence where the accused proves they reasonably believed the complainant was above a legally significant age. Under s.3(3), the relevant age is 17; the case concerned whether s.3(8) must also allow a reasonable mistake as to 15 (the court said no).
• “Peer consent” / “Romeo and Juliet” defence (s.3(8)): a limited exception recognising that consensual sexual activity between peers close in age may be treated differently, but only where the younger participant is at least 15 and other protective conditions are met.
• Capacity to consent: the law can declare that certain persons (here, children under 15) cannot give legally effective consent to sexual activity; even if they factually agreed, the law treats that agreement as invalid for certain offences/defences.
• Expressio unius est exclusio alterius: “to express one thing is to exclude another”. If legislation explicitly mentions one defence in one place but omits it in a closely related place, courts may infer the omission was intended.
• “Pure” equality claim vs proportionality: where someone says “others got a benefit; I should too,” the court asks whether excluding them is irrational/arbitrary (Donnelly rationality), not whether a more inclusive rule would be fairer or proportionate.
• Presumption of constitutionality: primary legislation is presumed constitutional; the challenger bears the burden to show invalidity.

5. Conclusion

Luke v DPP holds that the Constitution does not require extension of the s.3(8) peer-consent defence to cases where an accused reasonably but mistakenly believed the complainant had attained 15. The judgment anchors that conclusion in (i) the post-C.C. constitutional requirement that mens rea not be wholly abrogated—satisfied here by the s.3(3) reasonable-mistake-as-to-17 defence—and (ii) Article 40.1’s rationality test for “pure” equality claims, under which the 15-year threshold is a rational proxy for capacity to consent within a carefully limited legislative carve-out. The decision thereby reinforces legislative latitude in designing child-protection sexual offences, while clarifying that equality challenges in this area must demonstrate irrationality, not merely a plausible fairer alternative.