Article 40.4.2 Does Not Permit Class‑Wide Habeas: Specificity and Case‑Focus Required — Commentary on McGreal v Minister for Justice [2025] IEHC 597

Article 40.4.2 Does Not Permit Class‑Wide Habeas: Specificity and Case‑Focus Required

Case: McGreal v The Minister for Justice, Home Affairs and Migration & Ors [2025] IEHC 597 (High Court of Ireland, Cregan J, 31 October 2025)

Introduction

This High Court judgment addresses the procedural and substantive limits of the Irish constitutional remedy of habeas corpus under Article 40.4.2. The complainant, Patrick McGreal, styled as a “citizen of Ireland, greengrocer and Justice Facilitator,” invoked Article 40.4.2 not for himself or any named detainee, but “on behalf of any person” detained following prosecutions or convictions based on evidence obtained under search warrants issued by peace commissioners pursuant to section 26 of the Misuse of Drugs Act 1977 (as amended).

The case presented two core issues:

  • Whether procedural irregularities — specifically the absence of a record number — prevent the High Court from entertaining an Article 40.4.2 application; and
  • Whether Article 40.4.2 permits a court to open a habeas enquiry on a systemic, class-wide basis regarding an undefined and unknown set of detainees whose convictions allegedly rest on search warrants issued by peace commissioners.

While the Court reaffirmed the procedural flexibility and informality that characterise habeas corpus, it refused the application on the merits, holding that Article 40.4.2 does not authorise a roving, open-ended enquiry on behalf of an undefined class of unknown detainees. The decision draws a clear line between the breadth of who may apply (“by or on behalf of any person”) and the specificity required to trigger the Court’s immediate and targeted remedial powers.

Summary of the Judgment

  • Procedural informality affirmed. The absence of a record number does not bar the High Court from considering an Article 40.4.2 complaint. The Court requested the registrar to obtain a record number and proceeded (relying on Cahill v Governor of the Military Detention Barracks and Kane v Governor of Midland Prison).
  • Third-party standing accepted. The Court agreed that a complaint may be made “by or on behalf of any person.” Mr. McGreal, as a third party, could in principle bring an application on behalf of a detainee.
  • Specificity is essential. The application failed because it lacked identification of any specific detainee(s), place(s) of detention, or custodians. A class-wide, undefined category of persons does not meet Article 40.4.2’s requirements.
  • Speculative and unfocused claims are not suitable for Article 40. The Court characterised the application as speculative and akin to requesting a commission of investigation rather than a focused habeas enquiry.
  • Post-conviction detention presumed lawful. Where the purported class consists of convicted persons, detention ordinarily appears lawful, absent specific grounds undermining the order of detention.
  • Application refused. The Court declined to open an Article 40.4.2 enquiry on the facts presented.

Detailed Analysis

1) Precedents and Authorities Cited

The Court invoked established authorities to address the procedural gateway and the nature of an Article 40.4.2 enquiry:

  • Cahill v Governor of the Military Detention Barracks [1980] ILRM 191 (Finlay P): The Court emphasised the historically informal, flexible character of habeas corpus. An application can be made “in the most informal way,” even to a chosen High Court judge, and procedures are freed from many typical procedural constraints, reflecting the remedy’s immediacy and constitutional priority.
  • Kane v Governor of Midland Prison [2012] IEHC 511 (Charleton J): The Constitution confers a direct, swift right to challenge detention. The High Court may adopt procedures suitable to a proper enquiry, reinforcing that procedural rules should not abridge the constitutional remedy.

These precedents were applied to overcome the initial procedural objection (absence of a record number). Having ensured the case could proceed, the Court turned to the substantive threshold for opening an enquiry.

The applicant relied on other authorities to challenge the validity of peace commissioners exercising judicial power in criminal matters:

  • State (Clarke) v Roche [1987] ILRM 309 (as cited by the applicant); and
  • O’Mahoney v Melia [1989] IR 335 (as cited by the applicant).

The applicant argued these decisions confirm that peace commissioners, who are not judges within Articles 34 and 35, cannot exercise substantive judicial power in criminal matters — a fortiori not to issue search warrants requiring evaluative, judicial determinations on oath. He also referenced a Law Reform Commission report highlighting concerns with non-judicial actors issuing warrants. The Court did not resolve that constitutional issue; instead, it disposed of the application at the threshold for lack of specificity and focus, leaving such merits questions to be litigated in appropriate, case-specific proceedings.

2) The Court’s Legal Reasoning

Justice Cregan’s reasoning unfolds along four principal lines:

  1. Specific identification of the detainee(s) is required. Although Article 40.4.2 permits applications “by or on behalf of any person,” the remedy is framed to operate on a concrete, immediate basis: the Court may order the person in whose custody the detainee is held to produce the body and justify the detention. That practical structure presupposes a known detainee (or identifiable group) and a known custodian and place of detention. An application on behalf of an entire, unidentified class — “any person” detained in reliance on certain search warrants — is too vague and uncertain to trigger the remedy. The Court acknowledged that in some cases an applicant might not know the full or exact names of detainees, but a high degree of specificity is ordinarily present and required in Article 40 practice.
  2. The category posited is indeterminate and rests on speculative legal premises. The category was constructed from the applicant’s legal analysis about the constitutional validity of peace commissioners issuing search warrants under s.26 of the 1977 Act (as amended). The Court considered that analysis, made by a lay litigant, insufficient to warrant opening an enquiry. Without concrete, individualised facts showing unlawful detention, the claim was speculative.
  3. Presumption of lawfulness following conviction. The Court observed that the putative beneficiaries of the application are, effectively, persons tried and convicted in criminal courts. Such detention “appears” lawful unless specific grounds are shown to undermine the underlying order of detention. Article 40.4.2 is not designed as a vehicle for collaterally auditing classes of convictions through evidentiary challenges untethered to named detainees and particularised procedural history.
  4. Article 40 is not a commission of investigation. The applicant asked the Court at the “first stage” to direct the Minister, the Garda Commissioner, and the DPP to identify how many warrants were issued, by whom, and how many prosecutions and custodial sentences resulted. The Court declined, characterising this as an attempt to convert a targeted, immediate remedy into a broad, systemic investigation — a function outside Article 40.4.2’s remit.

3) What the Decision Clarifies

  • Standing remains broad; scope does not. A third party may bring an Article 40.4.2 application “on behalf of” a detainee. But the detainee(s) must be identified with sufficient specificity to allow the Court to issue workable orders.
  • Procedural informality is not a substitute for substantive precision. The Court will tolerate informality in initiating applications, including irregularities like lack of a record number, but will not open enquiries on speculative, class-wide claims detached from identifiable detentions.
  • No pronouncement on the constitutionality of peace commissioner warrants. The judgment leaves open (and does not decide) the underlying constitutional issues concerning peace commissioners’ authority to issue search warrants under s.26 of the 1977 Act. Those issues must be litigated in appropriate, case-specific proceedings or by suitable systemic constitutional challenge procedures — but not via a class-wide habeas application.

4) Likely Impact on Future Litigation and Practice

The ruling will have practical and doctrinal effects:

  • End of “class-action” habeas in Ireland. Petitioners cannot employ Article 40.4.2 as a mechanism for mass, unspecified challenges across a category of unknown detainees. Each Article 40 application must be tethered to identified detention(s).
  • Framing third-party applications. Third parties can still act “on behalf of” detainees, but should:
    • Identify the detainee(s) with reasonable precision (name if known; otherwise concrete descriptors sufficient to allow identification);
    • Identify the custodian and place of detention; and
    • Provide a concise factual-legal basis suggesting detention is not “in accordance with law.”
  • Appropriate procedural vehicles for systemic issues. Where litigants wish to test the constitutional validity of peace commissioner search warrants or other systemic practices, the appropriate avenues include individual criminal proceedings (motions to exclude evidence, appeals), targeted judicial review, declaratory proceedings, or legislative reform — not a class-wide Article 40 enquiry.
  • Practice note on initiation. Courts will ensure urgent access to Article 40 in keeping with Cahill and Kane. Administrative formalities (like record numbers) will not bar urgent constitutional oversight; registrars and judges can regularise such matters without defeating the remedy’s immediacy.

Complex Concepts Simplified

  • Habeas corpus (Article 40.4.2): A constitutional procedure allowing any person (or someone on their behalf) to urgently challenge the legality of detention. If the Court is satisfied that the person is detained otherwise than “in accordance with law,” it must order immediate release.
  • Two stages in practice:
    • Stage 1 (threshold): The Court decides whether to open an enquiry (often by issuing a conditional order). This requires enough specificity to identify the person detained and the custodian, and a credible basis for unlawfulness.
    • Stage 2 (enquiry): The custodian must produce the detainee and justify the detention. If justification fails, the Court orders release.
  • “On behalf of any person”: Article 40.4.2 allows third parties to apply, including where the detainee cannot act personally. But the detainee(s) must be specifically identifiable; it is not a licence for class-wide, undifferentiated claims.
  • Peace commissioners: Lay persons appointed by the Minister for Justice (not judges of the courts). Historically tasked with limited quasi-judicial functions, their involvement in issuing search warrants has been debated in light of the constitutional separation between judicial and non-judicial powers.
  • Search warrant vs summons: A search warrant authorises intrusion into private premises based on sworn information and a determination of reasonable grounds — evaluative functions often seen as judicial in nature. A summons, by contrast, is the instrument calling a person to court, historically involving more routine or administrative elements in certain contexts.
  • Article 37.1 (limited judicial functions): The Constitution allows non-courts to exercise “limited functions and powers of a judicial nature” in certain contexts. The applicant argued that issuing search warrants for serious drug offences exceeds that limit. The High Court did not decide that question in this case.
  • Commission of investigation (analogy): A formal, broad, systemic fact-finding process. The Court stressed that habeas corpus, being individualised and immediate, is not a substitute for such an investigation.

Key Precedents Explained (as used in this Judgment)

  • Cahill v Governor of the Military Detention Barracks [1980] ILRM 191: Affirms that habeas corpus is exceptional in its informality and urgency. Applications may be made without strict adherence to procedural rules; the Court focuses on the lawfulness of detention and may act swiftly, even when conventional formalities have not been observed.
  • Kane v Governor of Midland Prison [2012] IEHC 511: Reiterates that the Constitution is self-executing in conferring the right to habeas corpus and the High Court’s adaptability in crafting appropriate procedures to examine alleged unlawful detention.
  • State (Clarke) v Roche [1987] ILRM 309; O’Mahoney v Melia [1989] IR 335 (as cited by the applicant): Relied upon by the applicant to contend that peace commissioners, not being judges under Articles 34 and 35, cannot exercise substantive judicial powers in criminal matters (such as issuing evaluative search warrants). The High Court in this case did not adjudicate these constitutional contentions, as the application failed at the threshold for want of specificity.

What Practitioners Should Do After McGreal

  • For Article 40.4.2 applications:
    • Identify the detainee(s) and custodian(s) with enough detail to allow an order to be executed;
    • State the place of detention and the detention order being relied upon (if known);
    • Provide a succinct factual-legal basis indicating lack of lawfulness;
    • Use the remedy for concrete, immediate questions of unlawful detention — not generalised, systemic data-gathering.
  • For systemic challenges (e.g., to peace commissioner warrants):
    • Proceed via targeted constitutional proceedings, judicial review, or case-specific challenges within criminal trials/appeals (e.g., to admissibility of evidence).
    • Assemble a proper evidential record tailored to the legal issues, rather than seeking class-wide habeas relief.
  • Administrative note: Do not assume that missing paperwork (like a record number) will block Article 40 — but expect the Court to regularise the record while demanding substantive specificity about the detention.

Conclusion

McGreal v Minister for Justice sets a clear boundary on the scope of habeas corpus in Ireland: Article 40.4.2 remains an extraordinarily flexible and immediate constitutional remedy, but it is decidedly not a vehicle for open-ended, class-wide investigations into systemic issues. The Court reaffirmed that applications may be brought “by or on behalf of any person,” including by third parties, yet insisted that the detainee(s) be identified with sufficient precision to allow the Court to exercise its specific, coercive powers to produce the body and test the legality of custody.

The decision also underscores a pragmatic practice point: procedural irregularities at initiation will not sterilise the remedy — the Court can and will act to preserve Article 40’s efficacy. However, on substance, applicants must tie the constitutional complaint to concrete detentions, avoid speculative legal abstractions, and recognise that systemic constitutional questions (such as the role of peace commissioners in issuing search warrants) require different procedural routes and evidential records.

The key takeaway is twofold: flexibility in form, precision in substance. That dual emphasis both protects the immediacy and accessibility of habeas corpus and preserves its focused purpose — to free persons actually and specifically shown to be unlawfully detained.

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