Palatine DAC v An Bord Pleanála: Enhanced Duty to Give Reasons When Rejecting Inspector’s Assessment of Daylight and Sunlight Impacts

Palatine DAC v An Bord Pleanála [2025] IEHC 499: Enhanced Duty to Give Reasons When Rejecting an Inspector’s Assessment of Daylight and Sunlight Impacts

1. Introduction

This judgment of Farrell J in Palatine DAC v An Bord Pleanála & Ors [2025] IEHC 499 is a significant addition to Irish planning and administrative law. It focuses on the scope and intensity of the duty on An Bord Pleanála (“the Board”) to give reasons, particularly where:

  • the Board departs from the recommendation and analysis of its own Inspector,
  • the underlying issue involves technical and contested expert methodology (here, daylight and sunlight impacts), and
  • the issue has been specifically raised by objectors and is grounded in statutory and policy guidance (BRE Guidelines and the Dublin City Development Plan).

The case arises from a Board decision granting planning permission for a six-storey over basement office development at 94–95 Mount Street Lower and Love Lane, Dublin 2, after Dublin City Council had refused permission and the Board’s Inspector had recommended refusal.

Although the Applicant (Palatine DAC, the management company of the neighbouring residential scheme “Grattan Hall”) advanced a wide array of legal grounds—including jurisdiction, misapplication of national height guidelines, material contravention, EIA screening, and even constitutional/EU law challenges—the High Court ultimately quashed the decision on a single, tightly focused basis: the Board failed to provide adequate reasons, within the meaning of section 34(10) of the Planning and Development Act 2000 and general administrative law, for rejecting the Inspector’s detailed criticism of the developer’s daylight and sunlight assessment.

The judgment consolidates and sharpens the jurisprudence on reasons, especially where the Board rejects its Inspector on a core, technically disputed issue. It has immediate practical implications for how the Board drafts decisions in urban infill cases affecting residential daylight and sunlight.

2. Background and Planning Context

2.1 The parties and the site

  • Applicant: Palatine DAC, the owners’ management company for the neighbouring residential development “Grattan Hall”.
  • Respondents: An Bord Pleanála, Ireland, and the Attorney General.
  • Notice Party (Developer): Mount Way Offices Limited.

The development site comprised 94 and 95 Mount Street Lower and Love Lane in Dublin 2, an inner-city location adjoining existing apartment developments including:

  • Grattan Hall (Applicant’s property),
  • Ashford House, and
  • the Northumberlands (Love Lane).

2.2 Planning history

The developer applied in June 2020 for permission to demolish the existing two 3-storey over basement buildings and construct an eight-storey over basement office building (Reg. Ref. 2872/20).

Dublin City Council:

  • sought further information, including (crucially) a full visual assessment and a Vertical Sky Component (VSC) assessment for nearby residential developments, and
  • suggested reducing the height by two or three floors.

In response (May 2021), the developer:

  • revised its proposal to a seven-storey over basement building; and
  • submitted a Daylight Analysis and Overshadowing Report, expressly based on:
    • BRE 209, Site Layout Planning for Daylight and Sunlight: A Guide to Good Practice (2nd ed., 2011) (“BRE Guidelines”), and
    • the 2018 Apartment Design Guidelines.

Members of the public, including Palatine’s members, challenged the report’s conclusions and methodology. The Planning Officer ultimately recommended refusal on visual and residential amenity grounds (overlooking, overshadowing, scale, bulk, height, and massing), and Dublin City Council refused permission.

On appeal to the Board, the developer:

  • appealed the refusal, and
  • put forward a further alternative design: a six-storey over basement office building with reduced floor area and plot ratio, accompanied by updated daylight/sunlight material.

Palatine made detailed observations to the Board, again contesting the methodology and conclusions of the daylight/sunlight report and contending that the development would seriously injure the residential amenity of Grattan Hall and other nearby apartments.

2.3 The Inspector’s report and the Board’s decision

The Board’s Inspector recommended refusal. On daylight/sunlight, the Inspector found, in essence:

  • the developer’s daylight and overshadowing analyses were incorrect and unreliable having regard to BRE 2011, required by section 16.10 of the Dublin City Development Plan (“CDP”);
  • the studies were incomplete, reliant on an incorrect methodology and unacceptable thresholds (a 20% VSC standard instead of BRE’s 27%/0.8 test);
  • a significant percentage of affected windows in adjoining apartments were not assessed at all; and
  • it had not been satisfactorily demonstrated that the development would not have an undue adverse impact on residential amenity in terms of daylight and sunlight.

Despite this, the Board met in June 2022 and decided to grant permission (with fourteen conditions). The Board Direction and Order (sealed 1 September 2022) gave standardised reasons. As relevant to this case, the Board:

  • referred to:
    • the Z6 zoning in the Dublin City Development Plan,
    • the national Building Heights Guidelines 2018,
    • the central city location and pattern of development; and
  • concluded that, subject to conditions, the development would:
    • accord with national and local policy,
    • not adversely affect visual amenities, nor seriously injure residential amenities, and
    • be in accordance with proper planning and sustainable development.
  • expressly stated, in rejecting the Inspector’s recommendation, that:
    “… notwithstanding, that there would be an impact on the neighbouring buildings with regard to overshadowing, … the cumulative impact would not have undue negative impact, having regard to the built up nature of the site…”

The key dispute in judicial review was whether this level of reasoning was adequate given the contested expert evidence and the Inspector’s contrary findings.

3. Issues Before the High Court

Palatine pleaded a range of “Core Grounds” (1–7). In very brief outline:

  1. Jurisdiction: the Board allegedly acted without jurisdiction by granting permission for a materially different development (the appeal-stage revised scheme) from that refused by the planning authority.
  2. Urban Development and Building Heights Guidelines (SPPR 1 and SPPR 3): alleged unlawful reliance on, and misapplication of, these ministerial guidelines.
  3. Material contravention of the CDP: alleged failure to assess whether the development complied with the CDP (2016–2022) and, if not, unlawfulness in treating it as acceptable.
  4. Daylight/sunlight: alleged deficiencies in the developer’s daylight/sunlight analysis (BRE 209 and EN 17037) and the Board’s failure to adequately assess, and give reasons for accepting, that analysis.
  5. EIA screening: alleged deficiencies in the EIA preliminary examination in light of identified risks to visual and residential amenities.
  6. Core Ground 6 (modularised): constitutional/EU law challenge to Article 109(2) of the 2001 Regulations (as inserted by SI 296/2018) as being ultra vires section 3 of the European Communities Act 1972 and Article 15.2.1 of the Constitution.
  7. Core Ground 7 (modularised): challenge to section 37(2) of the 2000 Act as allegedly contravening the SEA Directive by permitting permission in contravention of the development plan.

Farrell J explicitly decided to address Core Ground 4 (daylight/sunlight and reasons) first, indicating that if that ground succeeded, it might be unnecessary to determine the others. That is exactly what transpired.

4. Summary of the Judgment

Farrell J quashed the Board’s decision by order of certiorari. The core holding is:

  • The Board failed to give adequate reasons, as required by:
    • section 34(10) of the Planning and Development Act 2000; and
    • general principles of administrative law,
  • for rejecting the Inspector’s finding that the developer’s daylight/sunlight methodology was deficient and unreliable.

The Court found:

  • The Board’s Direction and Order merely asserted that the cumulative overshadowing impact would not be unduly negative “having regard to the built up nature of the site”.
  • The Board did not explain:
    • why it considered the developer’s contested methodology (including the 20% VSC standard and partial window coverage) to be sound or sufficiently reliable, or
    • why it disagreed with the Inspector’s detailed conclusion that compliance with BRE-based standards had not been satisfactorily demonstrated.
  • Given:
    • the express reliance on BRE Guidelines by both developer and CDP,
    • the detailed submissions by objectors pointing out alleged methodological flaws, and
    • the Inspector’s reasoned rejection of the methodology,
    the Board had an enhanced duty to give reasons for rejecting that analysis. It failed to discharge that duty.

Because the reasons failure alone was sufficient to quash the permission, the Court expressly declined to decide the other grounds (including jurisdiction, SPPR issues, material contravention, EIA, or the constitutional/EU law challenges).

5. Detailed Analysis

5.1 The legal framework on reasons

5.1.1 Statutory duty – section 34(10)

Section 34(10)(a) of the Planning and Development Act 2000 provides:

“a decision given under this section or section 37 and the notification of the decision shall state the main reasons and considerations on which the decision is based…”.

Where the Board does not follow its Inspector’s recommendation, section 34(10)(b) requires:

“the main reasons for not accepting the recommendation in the report or reports to grant or refuse permission”.

Farrell J reiterates that these statutory obligations sit alongside the broader, common-law duty of administrative decision-makers to give reasons.

5.1.2 The general administrative law duty to give reasons

The judgment synthesises several key authorities:

  • Connelly v An Bord Pleanála [2018] IESC 31, [2021] 2 IR 752 – Clarke C.J. held that:
    • an affected person is entitled to know, in general terms, why a decision was made;
    • reasons must allow a person to consider whether to appeal or judicially review; and
    • reasons must allow a court to properly review the decision.
  • Balz v An Bord Pleanála [2019] IESC 90, [2023] 3 IR 751 – O’Donnell J stated that relevant submissions must be addressed and not simply ignored; this is central to maintaining public trust in decision-making.
  • Friends of the Irish Environment CLG & Anor v Minister for Housing… [2025] IECA 128 – Hyland J clarified that:
    • the duty to give reasons does not mean every submission must be answered;
    • only relevant submissions (relevant to the reasons for the decision) must be addressed, in light of Balz.
  • Balscaddan Road SSA Residents Association v An Bord Pleanála [2020] IEHC 586 and O’Donnell v An Bord Pleanála [2023] IEHC 381 – Humphreys J emphasised that a decision-maker must give the main reasons on the main issues, but need not provide “micro-specific” reasons on every sub-point.

Drawing these strands together, Farrell J confirms that:

  • The requirement is not for exhaustive detail; it is for clarity on the main reasons on the main issues.
  • However, where the main issues themselves are technically complex and contested, the reasons must be sufficient to show why the particular evidence and methodology chosen by the decision-maker were accepted.

5.2 Enhanced duty when rejecting an Inspector

A central theme of the judgment is the heightened reasons obligation when the Board departs from its Inspector’s recommendations and underlying analysis.

Farrell J cites Clonres CLG v An Bord Pleanála [2021] IEHC 303 and Flannery & Ors v An Bord Pleanála [2022] IEHC 83. In Clonres, Humphreys J explained that even apart from section 34(10)(b), there is an “independent administrative law requirement to give reasons which is enhanced where one is rejecting the inspector’s analysis”, for two basic reasons:

  1. If the Board does not accept the Inspector’s reasons, it must articulate its own reasons.
  2. The Board must engage with, and thus explain why it rejects, the Inspector’s rationale.

Farrell J fully endorses this approach. She also refers to Sherwin v An Bord Pleanála [2023] IEHC 26 and Ballyboden Tidy Towns Group v An Bord Pleanála [2022] IEHC 7, where Holland J noted that, if a decision-maker disagrees with another informed institutional actor (such as a planning authority or Inspector), the court and public must be able “in a meaningful way” to know why.

Applying that principle here:

  • The Inspector had given a reasoned and critical assessment of the developer’s daylight/sunlight reports, identifying specific methodological and evidential flaws.
  • The Board plainly disagreed with the Inspector’s analysis but only recorded a bare conclusion that overshadowing would not be “undue”, having regard to the built-up urban context.
  • There was no explanation at all of why the Inspector’s analysis was considered incorrect or why the developer’s methodology was considered acceptable.

This, the Court held, was not compatible with the statutory and common-law requirements on reasons.

5.3 Daylight/sunlight methodology: the factual dispute

5.3.1 Developer’s reports and the 20% VSC threshold

The developer’s consultants, H3D, produced a Daylight Analysis and Overshadowing Report (and later a supplement) using the BRE Guidelines. Key aspects were:

  • For “urban areas”, they suggested that a VSC of 20% is “good”, relying on an “Independent Review – Representation Hearing Report D&P/3067/03 – Appendix 1” prepared in relation to a London development.
  • They concluded that 95% of 98 windows analysed either:
    • exceeded 20% VSC, or
    • retained at least 0.8 of their existing VSC.
  • For a small number of windows (e.g. in Ashford House) failing at VSC level, they relied on Annual Probable Sunlight Hours (APSH) analyses to argue that overall sunlight would still be acceptable.

The report also stressed that the BRE guidance is not mandatory, should not be treated as rigid planning policy, and should be interpreted flexibly.

5.3.2 Objectors’ criticisms

Objectors (including the Applicant’s planning consultant, Jim Brogan) mounted a detailed critique:

  • The BRE Guidelines in fact use a 27% VSC standard (or 0.8 of the pre-development value), not a 20% threshold, for assessing adverse impact on existing dwellings.
  • The 20% figure derived from a London-specific independent review has no formal or obvious status in Irish planning policy.
  • Many significantly affected windows were omitted from the analysis, including:
    • 60 apartment windows on the northwest side of the Northumberlands, despite shadow studies indicating likely impact; and
    • additional Grattan Hall windows, especially on the east side.
  • For the windows that were assessed, when the proper 27%/0.8 BRE thresholds were applied, the failure rate was considerably higher than suggested by the developer.

In essence, objectors argued that:

  • the methodology was flawed and selectively applied;
  • the raw data was incomplete and selectively presented; and
  • the “95% compliance” figure was artificially constructed by departing from BRE’s own metrics and ignoring large numbers of affected windows.

5.3.3 The Inspector’s findings

The Inspector substantially upheld these criticisms. She found that:

  • There was “no dispute” that the neighbouring residential blocks would experience a diminution in outlook and skylight access.
  • The applicant’s analyses were not satisfactory to assess impacts against BRE’s 2011 standards.
  • Impacts on external private and communal open spaces were not assessed.
  • The developer’s assumption that 20% VSC was an acceptable threshold, instead of BRE’s 27%/0.8 formula, was not justified.
  • With the correct 27% VSC test, a substantially larger number of windows in neighbouring developments would fall below standards, resulting in perceptible loss of daylight.
  • There was a lack of survey information on the exact nature and function of affected windows in adjoining properties, and no design mitigation to address impacts.

The Inspector concluded that it had not been satisfactorily demonstrated that the development would avoid undue adverse impacts on neighbouring residential amenity in terms of daylight and sunlight.

5.4 The Board’s reasoning and the Court’s critique

5.4.1 The Board’s stated reasons

In rejecting the Inspector’s recommendation, the Board limited itself to the following reasoning on overshadowing/daylight:

“… notwithstanding, that there would be an impact on the neighbouring buildings with regard to overshadowing, [the Board] considered that … the cumulative impact would not have undue negative impact, having regard to the built up nature of the site…”

No explanation was given as to:

  • why the Board accepted the developer’s contested methodology;
  • how many windows were in fact considered to fail BRE-like metrics; or
  • why the 20% VSC standard from the London document was capable of replacing or modifying the BRE’s own metric in this Dublin context.

5.4.2 Converging “reasons triggers”

Farrell J is particularly clear that the daylight/sunlight issue attracted an especially strong obligation to provide reasons because three distinct sources of duty converged:

  1. Statutory/ministerial guidance under section 28:
    • The CDP expressly requires development to be “guided by” the BRE Guidelines (section 16.10).
    • The Board had also to consider the Building Height Guidelines, although SPPR3 was said (by the Board) not to apply directly.
  2. Submissions from third parties:
    • Objectors had made focused, technical submissions directly questioning the methodology and data of the developer’s report.
    • These were plainly relevant submissions within the meaning of Balz and the Court of Appeal’s clarification in Friends of the Irish Environment.
  3. Departure from the Inspector’s reasoned conclusion:
    • The Inspector had expressly found the analyses incomplete, flawed and unreliable.
    • By nonetheless granting permission, the Board implicitly rejected that analysis and thus triggered an enhanced duty to explain why, per Clonres, Flannery and Sherwin.

Farrell J remarks that any of these factors could independently give rise to a substantial obligation to articulate reasons. The fact that all three were present made the need for explanation unmistakable.

5.4.3 Main reasons on the main issues – not a “micro” point

The Board argued, in essence, that the impact on neighbouring buildings was a matter of “planning judgment” and that its short reasons sufficed. The Court rejected this characterisation.

Farrell J drew on Balscaddan Road and O’Donnell to distinguish between:

  • micro-level sub-issues, where courts accept that highly detailed reasons are not required, and
  • main issues, which require the Board to set out its main reasons, especially where there is a clash of expert evidence and a departure from an Inspector’s analysis.

The validity of the developer’s daylight/sunlight methodology was, in her view, plainly a main issue, not a sub-point:

  • It was central to whether residential amenity would be seriously injured.
  • It was a major plank of the planning authority’s refusal and the Inspector’s refusal recommendation.
  • It had been the subject of intensive submissions and contestation.

Explaining why and how the Board resolved the methodological conflict was therefore not a demand for micro-level reasoning; it was a demand to disclose the main reasons for its main conclusion.

5.4.4 The Court’s ultimate conclusion on reasons

At core, Farrell J held that:

  • An affected party such as the Applicant would not know why the Board considered the methodology sufficiently sound to reach a finding of “no undue negative impact”.
  • The sparse terms of the Direction and Order did not allow the Court itself to “engage properly” with the Board’s reasoning on this issue, as required by Connelly.
  • It was not an adequate answer to say “this is planning judgment”: there was a contested evidential basis and contested methodology that needed to be addressed, and it was not.

Accordingly, the decision was invalid for failure to give adequate reasons. The High Court granted an order of certiorari quashing the permission, without remitting the other grounds.

5.5 Treatment of ex post expert evidence

The Applicant had filed an affidavit and report from Amy Hastings, a daylight/sunlight expert, critiquing the developer’s methodology. The Board and the developer challenged the propriety of relying on expert evidence that had not been before the Board.

Farrell J carefully avoids deciding that dispute. She notes that it was unnecessary to rely on Hastings’ report to resolve the reasons issue. Instead, she confines herself to the record and submissions that were before the Board (including objectors’ criticisms and the Inspector’s analysis).

This underlines a familiar but important point in judicial review: the court reviews the lawfulness of the decision on the basis of the material before the decision-maker, rather than conducting its own, de novo technical evaluation.

6. Simplifying Key Legal and Technical Concepts

6.1 BRE Guidelines and daylight/sunlight assessment

The BRE 2011 document, Site Layout Planning for Daylight and Sunlight: A Guide to Good Practice, is a widely used technical guide in Ireland and the UK. While not legally binding in itself, it often acquires quasi-normative status because:

  • development plans (as here, the Dublin CDP 2016–2022, section 16.10) expressly state that development shall be “guided by” it; and
  • planners, inspectors and experts adopt its methodologies and thresholds as the reference standard.

Key BRE metrics include:

  • Vertical Sky Component (VSC): a measure (in percentage) of available daylight at a reference point on a window. BRE suggests that:
    • a VSC of 27% or more is good;
    • if, after development, the VSC remains above 27%, or is at least 0.8 (80%) of its pre-development value, adverse daylighting impact is unlikely.
  • Annual Probable Sunlight Hours (APSH): an assessment of the probable annual hours of direct sunlight received by a window, taking into account the site’s latitude and climate data.

The BRE stresses that its guidance is not mandatory rules and should be applied flexibly, especially in dense urban locations. Nonetheless, it provides the basic language and toolkit for assessing daylight and sunlight impacts.

6.2 27% vs 20% VSC

The dispute in this case revolved around whether it was legitimate to treat 20% VSC as a “good” standard in an urban setting, instead of the BRE’s 27%/0.8 rule.

The developer founded this 20% figure on a London-specific “Independent Review” (the Dalston scheme in Hackney), which suggested that, in inner-city environments, VSC in excess of 20% may be considered reasonably good and that mid-teen VSC values can still be acceptable.

The core points emerging from the judgment are:

  • The developer was free to draw on such material.
  • The Board was free, in principle, to accept lower VSC thresholds in dense city-centre contexts.
  • But if the Board is going to rely on a departure from the BRE norm—especially when the CDP itself anchors assessment to BRE—and that departure is criticised by objectors and an Inspector, then the Board must:
    • acknowledge the issue; and
    • give intelligible reasons for preferring the alternative standard and methodology.

The judgment does not hold that using a 20% VSC threshold is unlawful per se; it holds that accepting such a contested approach without reasons is unlawful.

6.3 Ministerial guidelines and development plans

Section 28 of the 2000 Act allows the Minister to issue guidelines (e.g. the Urban Development and Building Heights Guidelines 2018). Planning authorities and the Board must “have regard to” such guidelines in performing their functions.

Development plans, adopted by planning authorities, often incorporate or cross-refer to such guidelines and to technical standards, as the Dublin CDP did with the BRE Guidelines.

In this case:

  • The Board argued that it only had to “have regard to” the Building Height Guidelines, and that SPPR3 (the specific planning policy requirement dealing with building heights) did not directly apply.
  • The Court emphasised that there remained an autonomous duty to consider and explain how the relevant guidelines and incorporated standards influenced the decision, especially where daylight/sunlight impacts and the BRE methodology were central to the dispute.

6.4 Certiorari in planning judicial review

An order of certiorari quashes the impugned administrative decision, treating it as if it had never been made.

In planning judicial review:

  • certiorari is the standard remedy where a decision is found to be ultra vires, irrational, procedurally unfair, or inadequately reasoned;
  • the court does not generally substitute its own planning judgment; it simply removes the defective decision;
  • the matter may then return to the decision-maker for reconsideration, lawfully and with appropriate reasons.

Here, Farrell J made an order of certiorari quashing the Board’s decision and listed the matter for a later date for any consequential orders (for example, on costs or further procedural directions).

7. Implications and Impact

7.1 For An Bord Pleanála

The judgment sends a clear signal about the standard of reasoning expected when the Board:

  • confronts contested expert evidence on technically complex issues (daylight/sunlight, microclimate, noise, traffic modelling, etc.), and
  • chooses to disagree with the Inspector’s recommended outcome and critique.

Key practical consequences for the Board include:

  • More detailed and case-specific Directions: template or boilerplate reasons that merely cite zoning, general policy and urban context, without engaging with the critical contested issue, are now more vulnerable.
  • Engagement with methodology: the Board need not write a technical treatise, but it must:
    • acknowledge that the methodology was contested,
    • indicate why the Inspector was considered wrong or overly conservative, and
    • offer at least a brief explanation for accepting the developer’s approach.
  • Internal practice: Board members may need to ensure that the Board’s minutes and Direction accurately reflect the analytical path taken in dealing with expert disputes, so that the written decision transparently communicates that path.

7.2 For planning authorities and Inspectors

Planning authorities and Inspectors can draw some comfort from the judgment:

  • Their reasoned analyses, particularly on technical issues, cannot be lightly or silently brushed aside by the Board.
  • If the Board departs from their recommendation, it must meaningfully engage with the core reasoning behind their conclusion.
  • Detailed, transparent critiques of developer reports (e.g. identifying gaps in window coverage, misuse of thresholds, or lack of survey data) strengthen the requirement on the Board to address those points if it eventually grants permission.

7.3 For developers

Developers and their consultants should note:

  • Technical robustness: daylight/sunlight reports and similar technical studies must be methodologically sound and transparent. The more they “push the envelope” (e.g. by using non-standard thresholds or selective coverage), the more exposed they are to challenge if the Board accepts them without explanation.
  • Explaining deviations from guidelines: if relying on alternative standards (such as the 20% VSC threshold), developers should:
    • clearly justify why those standards are appropriate in the particular planning context; and
    • encourage the Board to record those justifications in its reasons.
  • Risk management: where Inspector and planning authority are critical of a report’s methodology, developers should be alert that a grant of permission is at higher litigation risk unless the Board’s decision expressly and cogently confronts those criticisms.

7.4 For objectors and community groups

For objectors, the decision is an important tool:

  • Technical objections to methodology (not merely outcomes) are powerful; if the Inspector adopts those objections and the Board then grants permission without clearly explaining why the methodology is nonetheless acceptable, that may be a strong basis for judicial review.
  • Submissions should:
    • identify specific methodological flaws, inconsistencies, and omissions;
    • link them to relevant guidelines (BRE, development plan policies, ministerial guidelines); and
    • show how they impact the core planning question (e.g. serious injury to residential amenity).
  • If the Board later dismisses such objections (or appears to do so by effectively siding with the developer’s reports), Palatine supports an argument that it must say why, in at least general and intelligible terms.

7.5 For the broader law on reasons

Doctrinally, the case:

  • reaffirms the “main reasons on the main issues” test, rooted in Connelly, Balz, Balscaddan Road and O’Donnell;
  • confirms that when:
    • national or adopted technical standards are in play,
    • submissions focus on those standards, and
    • the Inspector’s analysis adopts the criticisms,
    then the duty to give reasons is at its highest.
  • clarifies that this duty is not satisfied by “conclusion-only” statements, especially where the underlying methodology is itself the subject of the dispute.

The decision will likely be invoked beyond daylight/sunlight cases, wherever planning permissions hinge on contested modelling or technical standards (traffic, flood risk, air/noise pollution, etc.).

7.6 For daylight/sunlight litigation specifically

In the narrower field of daylight/sunlight impacts, Palatine is likely to:

  • encourage more rigorous, BRE-grounded assessments and transparent reporting of failure rates at neighbouring windows;
  • discourage reliance on foreign or ad hoc thresholds (such as 20% VSC) without clear justification and explicit treatment by the Board;
  • make it more difficult for the Board to accept heavily “optimistic” analyses that omit large groups of windows or external amenity spaces without giving reasons.

8. Limits and Unresolved Questions

The judgment is deliberately narrow in outcome, even if rich in reasoning. Farrell J expressly does not decide:

  • whether the Board had jurisdiction to grant permission for the revised, appeal-stage scheme (Core Ground 1);
  • the lawfulness of the Board’s approach to SPPR 1 and SPPR 3 of the 2018 Building Height Guidelines (Core Ground 2);
  • whether the decision involved or justified a material contravention of the Dublin CDP (Core Ground 3);
  • whether the EIA Preliminary Examination was deficient (Core Ground 5); or
  • the constitutional and EU law challenges to Article 109(2) of the 2001 Regulations and section 37(2) of the 2000 Act (Core Grounds 6 and 7).

Those issues remain open for future cases. In particular, the judgment does not pronounce on:

  • the legality of granting permission on appeal for a significantly revised scheme; or
  • the precise binding force, if any, of foreign authorities or reports (like the Hackney “Independent Review”) on Irish planning decisions.

Instead, the case stands as a focused decision on the standard of reasons where the Board rejects its Inspector’s assessment of technical evidence.

9. Conclusion

Palatine DAC v An Bord Pleanála is a carefully reasoned and practically important decision. Its core contribution can be summarised as follows:

  • The Board is fully entitled to disagree with its Inspector and to exercise its own planning judgment.
  • However, when doing so—especially on a technically complex and contested issue such as daylight/sunlight methodology—it must explain why it rejects the Inspector’s analysis and why it prefers the developer’s evidence.
  • That explanation need not be lengthy or hyper-technical, but it must go beyond bare assertions that impacts are not “undue” or that the site is “built up”. It must disclose the main reasons on the main issue.
  • Where development plans, ministerial guidelines and widely accepted technical standards (like the BRE Guidelines) are involved, and objectors’ submissions explicitly challenge a developer’s compliance with those standards, the reasons obligation is particularly stringent.

By quashing the permission solely on reasons grounds, Farrell J emphasises that transparency and intelligibility in decision-making are not optional “formalities” but core components of lawful planning administration. The case will likely shape how the Board structures its reasoning in future contentious, technically driven planning appeals, particularly in dense urban contexts where the trade-off between compact development and existing residential amenity is most acute.

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