Factual and Procedural Background
The Plaintiff challenged two decisions of the Defendant dated 18 July 2025 granting minor amendments to an existing, unchallenged permission for alterations to a wastewater treatment plant and associated percolation area (the Treatment Plant) located near The Town in The County. The amendments concerned (a) disconnection/capping and replacement of a gravity effluent pipe and associated works ("Gravity Effluent Pipe application") and (b) modifications to site access and internal roads ("Access Roads application"). Company A was the project developer and Company B was the planning authority at first instance (Company B was later struck out of these proceedings). Works under the parent permission were substantially completed in November 2023. The Plaintiff also instituted separate enforcement proceedings (s.160) against Company A in the Circuit Court alleging unauthorised development; those proceedings remain extant.
The Plaintiff sought certiorari quashing the two Defendant orders and related reliefs, grounding challenges in domestic law (including reliance on s.34(12) of the Planning and Development Act 2000), alleged failures of consideration of submissions, and alleged EU law defects (AA, WFD and EIA-related). Leave was granted; the main hearing occurred on 7 May 2026 before Judge Humphreys, who reserved judgment and delivered a reserved judgment dismissing the proceedings on 22 May 2026.
Legal Issues Presented
- Whether the Plaintiff's objections to the amended permissions constitute legal grounds rendering the Defendant's amending decisions null and void.
- Whether s.34(12) of the Planning and Development Act 2000 applied so as to require refusal of the applications because of alleged unauthorised development.
- Whether the Defendant's Appropriate Assessment (AA) and Water Framework Directive (WFD) and EIA-related assessments were legally adequate for the limited amendments under challenge.
- Whether the Defendant failed to have proper regard to submissions of the Plaintiff (irrationality challenge).
- Whether the Plaintiff has discharged the onus of proof required in judicial review to establish legal invalidity of the impugned decisions.
Arguments of the Parties
Plaintiff's Arguments
- Core contention that the amending decisions contain lacunae in the s.177V(1)(b) determinations and did not consider important environmental matters tied to existing development.
- Claim that the Defendant failed to refuse to consider the applications under s.34(12) because development carried out deviated from the parent permission (alleged unauthorised development).
- Allegation that the Defendant ignored or failed to give proper regard to the Plaintiff's submissions, including concerns about flooding, discharge to a swallow hole and impacts on groundwater and private wells.
- EU law complaints that decisions contravene provisions of the Water Framework Directive, the EIA Directive and the Habitats Directive.
Defendant's Arguments
- The assessments (AA, WFD screening and conclusions on EIA non-applicability) were lawful, adequately reasoned and open to the Defendant on the materials before it.
- Section 34(12) did not apply because the applications were not for retention of unauthorised development but for prospective works; the alleged unauthorised development had not been judicially established.
- The Defendant is not required to perform planning enforcement in an appeals process; allegations of unauthorised development were outside the scope of the appeals.
- The Plaintiff failed to discharge the onus of proof with admissible expert evidence and relied largely on assertion; the decision documents explicitly record that submissions were considered.
Company A's Arguments
- The Company A contended that the NIS and other materials treated the constructed Treatment Plant as part of the baseline for in‑combination assessment and that no expert evidence established any lacuna in the AA or WFD assessments.
- Company A denied that the impugned decisions authorised any direct discharge of pollutants to groundwater and relied on the expert and technical material before the Defendant.
- Company A also submitted that alleged points going beyond pleadings should not be entertained and that many complaints amounted to impermissible collateral challenges to the parent permission.
Company B's Position
- Company B's internal environmental officer had identified matters for consideration but proceeded to assess the applications and concluded, subject to mitigation, that no adverse effects arose; those assessments were placed before the Defendant.
- Company B's s.5 declaration (administrative record) indicated certain excavations fell within the parent permission.
Table of Precedents Cited
| Precedent |
Rule or Principle Cited For |
Application by the Court |
| Amariei v. Chief Appeals Officer [2026] IESC 22 |
Emphasised that an applicant must discharge the onus of proof to establish all facts necessary for relief. |
Cited to reinforce that the Plaintiff bore the evidential onus to establish facts underpinning challenge to the amending permissions. |
| Meadows v. Minister for Justice, Equality and Law Reform [2010] IESC 3 |
Onus of proof principle in judicial review. |
Used to support the requirement that the Plaintiff discharge the evidential burden. |
| O'Doherty and Waters v. Minister for Health [2022] IESC 32 |
Onus remains on applicant even in constitutional challenges. |
Applied to reject shifting burden to respondents in the absence of evidence. |
| An Taisce v. An Bord Pleanála & Ors [2022] IESC 8 |
Onus to show defect in environmental assessment generally lies on the applicant; EIA duties explained. |
Relied on to require evidential demonstration of AA/EIA/WFD defects by the Plaintiff. |
| G.K. v. Minister for Justice, Equality and Law Reform [2002] 2 I.R. 418 |
Presumption that material has been considered if the decision-taker says so. |
Applied to hold that Plaintiff had not rebutted the presumption that submissions were considered. |
| Sweeney v. Fahy [2014] IESC 50 |
Judicial review concerned with legality rather than merits. |
Used to emphasise the court's limited role and to reject merits-based reweighing of planning judgments. |
| State (Keegan) v. Stardust Compensation Tribunal [1986] I.R. 642 |
Limits on judicial substitution for administrative decision-making (legality vs merits). |
Invoked to underline separation of powers and review scope. |
| Illegal Immigrants (Trafficking) Bill 1999 [2000] IESC 19 |
Doctrine against collateral challenges to previous unchallenged decisions applies in EU law context. |
Applied to bar collateral attack on the unchallenged parent permission via the amendment applications. |
| Rachki v. Governor of Cloverhill (Unreported, Supreme Court, 5 December 2011) ex tempore |
Same principle against collateral challenge reiterated. |
Reinforced that unchallenged permissions stand and cannot be reopened collaterally here. |
| Concerned Residents of Treascon and Clondoolusk v. An Bord Pleanála [2024] IESC 28 |
EIA directive does not apply to projects that are not listed. |
Applied to confirm that EIA obligations do not extend beyond listed project types; relevant to EIA screening here. |
| Reilly v. An Coimisiún Pleanála [2025] IEHC 659 |
Outlined cumulative tests for relief by judicial review in planning cases. |
Adopted as framework (eight-fold path) for assessing whether relief should be granted. |
| Foran v. An Coimisiún Pleanála & Glenveagh [2026] IEHC 23 |
Further illustration of judicial review thresholds in planning context. |
Used to support application of the judicial review tests described. |
| R (Cart) v. Upper Tribunal [2011] UKSC 28 |
Caution that legal argument should not masquerade as merits-based attack. |
Invoked to discourage dressing merits complaints as legal errors. |
| Tesco Stores Ltd v. Secretary of State for the Environment [1995] 1 W.L.R. 759 |
Weight of evaluative judgments is for the decision-maker. |
Used to support deference to planning evaluative judgments absent legal error. |
| Baby O v. Minister for Justice [2002] IESC 44 |
Evaluative judgment deference to administrative decision-taker. |
Reiterated that assessment of evidence weight is for the authority, not the court. |
| R. (Friends of the Earth Ltd) v. Heathrow Airport Ltd [2020] UKSC 52 |
AA/EIA principles; iterative nature of assessments and proper standards. |
Referenced for principles on iterative assessments and standard of review in environmental cases. |
| H.A. v. Minister for Justice [2022] IECA 166 |
If an applicant demonstrates error, onus shifts to opposing parties to show harmlessness. |
Applied to explain burden shifting where an error is proved (not the case here). |
| Murphy v. An Bord Pleanála [2009] IEHC 38 |
Limits of the role of appeals body regarding enforcement and unauthorised development. |
Used to support that enforcement questions are generally for planning authority/courts, not appeals process. |
| R (Hoareau and Bancoult) v. Secretary of State for Foreign and Commonwealth Affairs [2019] EWHC 221 |
Judicial review is not politics by other means; separation of powers. |
Invoked to caution against policy substitution by courts. |
| O'Sullivan v. Health Service Executive [2023] IESC 11 |
Guidance on draft judgment procedure and limits of procedural reargument. |
Referred to in relation to draft judgment circulation and limited scope of comments. |
| Attorney General v. Crosland (No. 2) [2021] UKSC 58 |
Reasons for restricting publication of draft judgments. |
Invoked to justify confidentiality direction for draft judgment circulation. |
| Other authorities cited in the judgment (select list as referenced): |
Various principles on presumption of validity, standards of AA/EIA, evaluative deference, pleading requirements and onus of proof. |
The Court summarised and applied these established principles to the facts and procedural posture of this case. |
Court's Reasoning and Analysis
Judge Humphreys applied settled judicial review principles to the challenge to modest amendments of an already-consented Treatment Plant. The analysis proceeded as follows.
1. Threshold framework: The court applied an eight-fold test for relief (jurisdictional compliance, legal correctness, particularity of pleading, standing, material before decision-taker, onus of proof, materiality of any error, and discretion) drawn from recent authorities; judicial review is concerned with legality not merits.
2. Onus of proof and evidence: The court held that the Plaintiff bore the onus to demonstrate all facts necessary for relief, including any scientific or expert evidence required to show defects in AA/WFD/EIA assessments. Mere assertion, non-expert opinion or reliance on unproven allegations of unauthorised development was insufficient.
3. Scope of the decision under review: The Defendant and inspector had limited remit to assess the specific amendment applications; they were not obliged to re‑open, or to act as an enforcement body with investigatory powers to determine alleged pre-existing unauthorised development. Section 34(12) applies to applications to retain unauthorised development and did not apply to the prospective amendment applications before the Defendant.
4. Collateral challenge doctrine: The court emphasised that unchallenged prior permissions stand and that the Plaintiff could not use the amendment process as a vehicle to collaterally impugn the 2020 parent permission absent appropriate proof; cases establishing the doctrine were applied.
5. Assessment adequacy: The court found the record (NIS, SSFRA, inspector's reports, council's assessments) showed consideration of in‑combination effects with the constructed Treatment Plant and adequate screening for AA and WFD in the limited context of the proposed amendments. The court concluded the Plaintiff had not shown an evidential lacuna or created reasonable scientific doubt requiring intervention.
6. Regard to submissions: The Defendant's decisions expressly recorded that submissions and expert materials were considered. There is a presumption that material stated to have been considered was considered; the Plaintiff had not discharged the onus to rebut that presumption. Alleged failures of "proper" regard were treated as merits complaints unsuitable for judicial review without evidence of legal error.
7. EIA scope: The court applied authority that EIA obligations apply only to listed project types; the proposed amendments fell outside EIA-listed classes and no EIA screening requirement arose.
8. Disposition and proportionality: Even if limited imperfections were arguable, the court would not quash the permissions in circumstances where errors (if any) were not shown to be material, and where relief would be disproportionate given the narrow and remedial nature of the amendments and the absence of evidential displacement of the Defendant's conclusions.
Holding and Implications
HOLDING: The court ordered that the proceedings be dismissed.
Implications:
- The direct effect is that the Defendant's orders dated 18 July 2025 granting the two amendments remain valid and are not quashed.
- The Plaintiff's judicial review challenge failed for lack of evidential discharge of the onus of proof, for being largely merits-based or collateral to the unchallenged parent permission, and because statutory provisions (including s.34(12)) did not apply to the applications under challenge.
- The judgment records a provisional order as to costs of no order, subject to further written applications in a limited timeframe; the dismissal does not purport to create new precedent beyond application of settled principles to the facts.