Planning Conditions Are Not “Necessary” Where Major-Hazard Pipeline Risks Are Adequately Controlled by HSE Oversight and Statutory Safety Regimes

1) Introduction

In [2026] CSIH 29 (First Division, Inner House, Court of Session), the court (opinion delivered by Lady Wise, with the Lord President and Lord Clark) refused an appeal under section 239 of the Town and Country Planning (Scotland) Act 1997. The appellants (Shell Chemicals UK Limited and Shell UK Limited, “Shell UK”) challenged a reporter’s decision for the Scottish Ministers granting permission for an extension of mineral extraction at Duneaton Quarry and, critically, removing a condition that had required relocation of Shell UK’s major-hazard ethylene pipeline before quarry extension works commenced.

The pipeline is a major hazard pipeline regulated by the Health and Safety Executive (“HSE”) and governed by the Pipelines Safety Regulations 1996, while the quarry is subject to the Quarries Regulations 1999. A private deed of servitude between Shell UK and the quarry operator’s predecessor also governed protective arrangements around the pipeline.

The core legal issue was whether, applying the policy tests for planning conditions in Planning Circular 4/1998, it was necessary (and reasonable/enforceable) for planning permission to include a condition requiring pipeline relocation prior to commencement—or whether safety was sufficiently secured by existing statutory controls and regulatory oversight such that the condition would be unnecessary duplication.

2) Summary of the Judgment

  • The court held the reporter made no legal error in removing the pipeline-relocation condition: the decision was grounded primarily on statutory health and safety controls and HSE oversight, not on private rights under the servitude.
  • The reporter was entitled to conclude that a relocation condition was not “necessary” under Planning Circular 4/1998, and that the original condition was unreasonable because the developer could not deliver relocation without the pipeline operator’s cooperation.
  • The court rejected challenges based on (i) alleged reliance on an immaterial private agreement, (ii) irrationality/inadequate reasoning, (iii) alleged misunderstanding of HSE advice, (iv) alleged non-compliance with NPF4 Policy 18 (infrastructure mitigation), and (v) alleged inadequacy of EIA regarding pipeline diversion.
  • The appeal was refused in full.

3) Analysis

3.1 Precedents Cited and Their Role

(a) Private rights and planning relevance

Shell UK relied on Brewer v Secretary of State for the Environment [1988] 2 PLR 13 and Stringer v Minister of Housing and Local Government and Another [1971] 1 All ER 65 to argue that private land law arrangements (the servitude) are irrelevant to planning decision-making, so reliance on them would be reliance on an immaterial factor.

The court accepted the general point that planning is concerned with public interest, not private bargains, but held that the reporter did not determine necessity by treating the servitude as the controlling public-safety mechanism. Rather, the servitude formed background context to the parties’ dispute and illustrated that Shell UK had a separate private mechanism to halt risky activity; the decisive reasoning rested on statutory regulation and HSE guidance.

(b) Material considerations and weight

Shell UK invoked Tesco Stores v Environment Secretary [1995] 1 WLR 759 to argue the reporter relied on immaterial factors and misapplied judgment. The court used Tesco Stores in the orthodox way: the weight to give to relevant material (including HSE advice) is for the decision-maker, reviewable only on public law grounds. The reporter’s approach fell within planning judgment.

(c) Conditions and “other controls”

The court addressed Shell UK’s reliance on Elsick Development v Aberdeen City & Shire SDPA [2017] UKSC 66; 2018 SC (UKSC) 75 (paras 29–32) as authority on conditions and the relevance of other regulatory regimes. It treated the case as reinforcing that the question is whether a condition is truly needed, including whether it duplicates other controls. Here, the reporter was entitled to find that the statutory health and safety regime and HSE oversight adequately controlled the relevant safety risks.

(d) Adequacy of reasoning

Shell UK relied on Wordie Property Co Ltd v Secretary of State for Scotland 1984 SLT 345 to attack the alleged inconsistency and inadequacy of reasons. The court held that the reporter’s differing treatment of the pipeline-relocation condition and the vibration condition demonstrated application of the necessity/reasonableness tests to different risk-control contexts, not contradiction.

(e) Timing of mitigation and reliance on regulatory intervention

Shell UK cited Hopkins Developments Ltd v First Secretary of State [2006] EWHC 2823 (Admin); [2007] Env LR 14 to argue that safety should be secured up front by condition rather than left to later regulatory action. The court rejected the factual premise that work would realistically proceed unlawfully or unsafely: the HSE could prevent unsafe works, and both operator and developer were subject to direct statutory duties.

(f) EIA scope, “single project”, and inevitable indirect effects

On EIA, Shell UK relied on Raeshaw Farms v Scottish Ministers [2026] CSIH 10; 2026 SLT 183 and (R Finch) v Surrey County Council [2024] UKSC 20; [2024] PTSR 988 to argue that pipeline diversion was an inevitable part of the project and had to be assessed in detail as an indirect effect.

The court distinguished Raeshaw (where there was a flawed evaluation of whether elements formed a single project). Here, the reporter was entitled to accept a high-level assessment because the future route and effects of a diversion were unknown and not part of the quarry extension proposal before him; the EIA and supplementary material assessed diversion as far as possible given those uncertainties.

3.2 Legal Reasoning

(a) The governing test: necessity (and the six policy tests)

The legal anchor was Planning Circular 4/1998, requiring conditions to be: necessary, relevant to planning, relevant to the development, enforceable, precise, and reasonable. The court emphasised that necessity is “important but not sufficient”: not every relevant matter must be controlled by condition; there must be a “definite need”.

(b) Why the pipeline-relocation condition was lawfully removed

The court endorsed the reporter’s key steps:

  1. Practicality/reasonableness: the original condition required the developer to produce details demonstrating safe relocation, including HSE authorisations, but the developer was not the pipeline operator and would be dependent on Shell UK’s cooperation. The reporter was entitled to regard that as an unreasonable planning requirement.
  2. Duplication/other controls: HSE’s statutory remit and the safety regimes under the Pipelines Safety Regulations 1996 and Quarries Regulations 1999 were capable of controlling the relevant public safety risks, making a planning condition unnecessary duplication.
  3. HSE advice as evidential foundation: the HSE did not advise against the proposal and did not recommend a planning condition to ensure pipeline removal before works commenced. The reporter was entitled to treat that as significant.
  4. Focus on public safety, not asset protection: while Shell UK framed the condition as protecting pipeline integrity as an asset, the reporter properly approached the matter through the lens of public safety (the rationale for the original condition).

(c) Why the servitude did not become a “material consideration” error

The court’s central clarification is that noting a private legal mechanism is not the same as treating it as a substitute planning control. The servitude featured as context to the parties’ dispute and as an illustration that Shell UK had private remedies; but the reporter’s conclusion on necessity rested on statutory obligations and HSE oversight.

(d) Alleged “onus inversion” under section 42

Shell UK argued the reporter inverted the onus (asserting the applicant under section 42 must justify deletion/variation of conditions). The court read the decision as a whole and held the reporter was testing and assessing safety controls, not reversing legal burdens.

(e) Consistency with the vibration condition

The vibration condition (formerly requiring Shell UK’s confirmation of acceptable vibration) was replaced with an objective limit (50 mm/s ppv). The court held the comparison supported, rather than undermined, the reporter’s approach: where Shell UK would effectively control commencement without a public duty, the condition was unreasonable; where objective monitoring could secure safety, a condition was justified.

(f) NPF4 Policy 18 (infrastructure mitigation)

The court rejected the proposition that mitigation must be “controlled by the planning authority” through conditions. It accepted that mitigation can be secured via statutory schemes; therefore, removal of the planning condition did not necessarily breach Policy 18 of National Planning Framework 4.

(g) EIA adequacy

Applying regulation 4(2) of the Town and Country Planning (Environmental Impact Assessment) (Scotland) Regulations 2017 (assessment of direct and indirect significant effects “in an appropriate manner”), the court held that a high-level assessment of diversion was sufficient given uncertainty as to route and the fact that diversion was not itself a defined element of the application being determined.

3.3 Impact

  • Conditions vs. regulatory regimes: the decision reinforces that where robust, enforceable statutory safety controls exist (and a specialist regulator is actively engaged), planning conditions may be struck down as unnecessary duplication—particularly if they require outcomes dependent on third-party cooperation.
  • Major-hazard infrastructure contexts: for development near major hazard pipelines, decision-makers can place substantial reliance on HSE advice and statutory duties under the Pipelines Safety Regulations 1996 and Quarries Regulations 1999 when assessing whether planning conditions are needed for public safety.
  • Drafting conditions: the case illustrates the vulnerability of conditions that effectively confer a private party veto or require proof of compliance with a private agreement (risking unenforceability/imprecision).
  • EIA pragmatism: it supports a proportionate approach to EIA where an associated future activity (like a diversion) is not sufficiently defined to permit detailed assessment, provided the EIA addresses it to the extent reasonably possible and avoids improper project splitting.

4) Complex Concepts Simplified

Section 42 application
A mechanism to seek a fresh permission for the same development but without complying with (i.e., deleting or changing) specified conditions. The decision-maker reassesses the conditions against policy tests (not simply whether the developer dislikes them).
The “six tests” for conditions (Planning Circular 4/1998)
A planning condition must be necessary; relevant to planning; relevant to the permitted development; enforceable; precise; and reasonable. If a condition fails one of these (e.g., depends on someone else’s cooperation, or duplicates a statutory regime), it is vulnerable.
Duplication of other controls
Planning should not routinely re-regulate matters already adequately controlled by other legal regimes (such as health and safety regulation). If other controls sufficiently manage the risk, a planning condition can be “unnecessary” and therefore unlawful/unreasonable.
Planning permission is a consent, not a command
Granting permission allows development but does not compel the developer to proceed; if other regimes prevent safe execution, the developer may be unable (lawfully or practically) to implement it.
EIA “indirect effects” and uncertainty
EIAs must assess likely significant effects, including indirect ones, but the assessment must be “appropriate”. If a future element is not yet defined (e.g., route unknown), detailed assessment may be impossible; a high-level assessment may suffice until details crystallise.

5) Conclusion

[2026] CSIH 29 affirms a practical, regulator-aware approach to the “necessity” of planning conditions. In a setting involving a major-hazard pipeline, the Inner House upheld the reporter’s conclusion that public safety could be adequately protected by statutory health and safety duties and HSE oversight, making a pipeline-relocation planning condition unnecessary (and, as framed, unreasonable).

The case is a reminder that conditions must do planning work that genuinely needs to be done; they cannot be used to duplicate effective statutory regimes or to force outcomes dependent on third-party action, and EIA obligations will be judged against what can realistically be assessed given the definition (or lack of definition) of associated future works.