Deep Dive: Lessons From The Gatwick Airport Judicial Review Claims

As has been widely reported, on 4 August 2026 the Court of Appeal refused permission to appeal to both of the objectors who brought legal challenges against the grant of development consent for Gatwick Airport's Northern Runway Project (NRP). As a permission to appeal decision cannot be appealed on to the Supreme Court, this marks the end of both legal challenges and, therefore, the conclusion of a near-decade-long process from initial project conception to a challenge-free consent. 

Herbert Smith Freehills Kramer acted for Gatwick Airport on the application and examination of the project and as Interested Party in the subsequent judicial review claims. In this article we reflect on the claims, noting points from the judgments that are of potential wider relevance and considering what the claims tell us about the effectiveness of the Government's recent procedural reforms to judicial review. 

The project

By way of recap, the NRP involves the repositioning of Gatwick's existing northern runway 12 metres to the north to allow dual runway operations with the main runway which, together with other airfield infrastructure works, terminal extensions and highway improvements, will help unlock significant growth at the airport. The £2.2 billion scheme will be privately financed and is forecast to create circa 14,000 jobs in the South-East and inject £1 billion into the region's economy every year. 

Gatwick submitted its application in July 2023 and development consent was eventually granted by the Secretary of State for Transport (SST) in September 2025, after the SST had first taken the unusual step in February 2025 of issuing a 'minded to approve' letter and requesting further information. 

The claims

Two objectors to the scheme brought claims for judicial review: Communities Against Gatwick Noise Emissions (CAGNE) and Mr Peter Barclay. Between them, the claims initially comprised a combined 12 grounds, including issues relating to the SST's assessment of greenhouse gas (GHG) emissions, interpretation of aviation planning policy and consideration of noise and economic benefits. One of CAGNE's grounds depended on a separate judicial review claim to the lawfulness of the Government's Jet Zero Strategy (JZS) and was withdrawn when that challenge failed in November 2025. A full summary of the grounds is set out in Table 1 below. 

The claims were heard together at a 'rolled-up hearing' in the High Court between 20-23 January 2026 that considered both permission to bring judicial review and the substantive merit of the claims. In a comprehensive judgment handed down on 23 June 2026, Mr Justice Mould dismissed the claims in their entirety. 

Undeterred, both claimants applied for permission to appeal certain of their grounds, shown in the far right column in Table 1 below. Holgate LJ in the Court of Appeal swiftly set an expedited timetable for an oral permission hearing on 27-28 July 2026, guided by the newly implemented target timescales for appeals in nationally significant infrastructure project (NSIP) cases in CPR Practice Direction 52D introduced as part of the Government's judicial review reforms. CAGNE attempted an argument that the expedited timetable breached its right to a fair trial under Article 6 of the European Convention on Human Rights, but the Court of Appeal was (rightfully) unpersuaded.

The oral hearing took place across 1.5 days on 27-28 July 2026 before a panel of Holgate LJ and Dove LJ, both highly experienced planning specialist judges. Just one week later, the judges handed down a thorough, 29-page judgment refusing permission to appeal on all grounds. 

Legal points to note from the judgments

Naturally, much of the two claims related to matters specific to the NRP and this particular decision letter. However, there are several notable points with potential relevance beyond this scheme, particularly for other aviation expansion projects that might be on the horizon (not mentioning any names…) 

Interpretation of the Airports National Policy Statement ( ANPS )

The High Court and Court of Appeal dismissed Mr Barclay's argument that the ANPS does not support expansion at Gatwick Airport, or at least not to the extent comprised in the NRP.

Interpreting that policy, the Court of Appeal held that the ANPS, together with the Government policy document 'Making best use of existing runways' (June 2018) (MBU) (our emphasis): 

1. "specially contemplated that proposals for increased capacity  at airports other than Heathrow (for which there was a specific scheme for a new runway) by way of making best use of existing runways  would be supported, subject to the satisfaction of environmental concerns and… a demonstrable need… additional or different… to that being met by [Heathrow's North-West Runway]" [23]; and
2. "there is  no cap on the scale of proposals that can be brought forward under the ANPS and MBU policy and in particular proposals which would lead to an increase of in excess of 10mppa are expressly contemplated" [24]. 

These are useful conclusions for non-Heathrow airports seeking to rely upon ANPS and MBU for large-scale expansion projects to better utilise their existing runways. Of course, the ANPS is likely to shortly be replaced by the new Heathrow Expansion NPS (HENPS) – however, the draft HENPS retains similar wording on airports beyond Heathrow making best use of their existing runways and explicitly reaffirms support for MBU (see para. 1.23), and thus analogies can likely be drawn from the judgment's treatment of the ANPS. 

No need for a decision-maker to resolve every dispute

Mr Barclay's other appealed ground was relatively project-specific, attacking the SST for not having expressly dealt with a particular dispute between an objector group and the applicant on Gatwick's business passenger forecasts and the economic value ascribed to those passengers. This ground was rejected. 

The point of useful wider application in this respect was the Court of Appeal's reminder that, where there is a "wide variety of evidential material [and] policy" from which a decision-maker can draw conclusions and on which they can place weight, "[t]he selection of the evidence to be relied upon and the weight to attach to it was entirely a matter for the ExA and the SST" [34] – they are matters of judgment for the decision-maker. This is provided they are fully reasoned and that the matters left out of account are not mandatory material considerations. 

In relation to giving reasons, full reasons are not needed on every technical dispute aired during an examination, where that dispute is not a "principal controversial issue" [34]. 

Distinction between the significance of GHG emissions and their policy implications

CAGNE's argument that it was irrational for the SST to conclude that GHG emissions from the project would have a 'moderate adverse' significant effect for Environmental Impact Assessment (EIA) purposes (applying the seminal practitioner IEMA¹ Guidance) but that they would not be "so significant that it would have a material impact on the ability of government to meet its carbon reduction targets" (this being the policy test under ANPS para. 5.82) was also dismissed. 

The Court of Appeal held that a development "may not be fully compatible with the UK's net zero trajectory, as the SST found to be the case here, but… still not materially impact upon the UK's ability to meet its net zero [sic] and the carbon budgets". Such a finding was held not to involve any "inherent contradiction" because there are "degrees of compatibility" [46]. 

The Court of Appeal was also assisted by the SST's conclusion here that falling short in fully contributing to net zero would be "mitigated in the long term" by other Government policy (here, the JZS). 

This is a useful steer for developers preparing Environmental Statement (ES) chapters on GHG, particularly in an aviation context, and shows that even significant effects for EIA purposes can rationally be concluded to be policy compliant and to not jeopardise the long-term achievement of the UK's climate targets. 

Application of  Finch  to GHG effects and need for quantification 

Both Courts disagreed with CAGNE's argument that it was irrational for the SST not to require that non-CO₂ emissions be quantified as part of her consideration of the significance of GHG emissions, and that this was contrary to the precautionary principle. 

The Court of Appeal noted that the Supreme Court case of Finch confirmed that "insufficiency of evidence may be relevant to a decision-maker's judgment as to the adequacy of the nature and scope of EIA…" [56]. Whilst the precautionary principle "requires a high standard of investigation… its application ultimately rests on the judgment of the decision-maker" [57]. 

Here, many submissions were made to the SST during the examination and decision stage regarding the need or not to quantify non-CO₂ emissions, and the methods which might be deployed to do so. Gatwick Airport asserted that, given the uncertainty as to a settled method and the difficulty in contextualising any resulting figure (as UK carbon budgets do not account for non-CO₂), a qualitative assessment was an appropriate and lawful approach. The SST ultimately agreed, and took non-CO₂ emissions into account in her conclusions on that basis, treating them as an additional negative impact of the project. 

The Court of Appeal concluded that this was an "adequate assessment of those emissions for the purposes of EIA" and that the approach was not arguably irrational. Indeed, the Court went so far as to say that the SST's conclusion in this respect was "not surprising given that… the representations [the SST] received did not make any real attempt to show that the two [ways of quantifying non-CO₂ emissions] put forward used a method which overcame the ExA's concerns [at the lack of an agreed or settled methodology]" [68]. 

This is a useful confirmation of the lawful approach to EIA of non-CO₂ emissions, following similar findings in previous High Court cases relating to Bristol Airport (BAAN) and Luton Airport (LADACAN).

Interestingly, CAGNE did not appeal the High Court's dismissal of its related ground that the SST's treatment of inbound flight emissions was unlawful. The SST had concluded that, given inbound flight emissions are also not encompassed within UK national carbon budgets, there could be no meaningful quantitative assessment of them against a relevant benchmark. Hence, a qualitative assessment was appropriate. 

The High Court found the SST's approach to be lawful, with Mould J concluding that: 

"There is no legal principle which requires a public authority deciding whether to grant a development consent to contextualise GHG emissions or to compare them with a benchmark." [230]

Reliance on Government policies

CAGNE was unsuccessful in its assertion that the SST erred in placing reliance on the policy and assumptions in the JZS when consenting the NRP. Gatwick had argued that it was reasonable for it and the SST to rely on this document given that it represents extant Government policy and that the policy itself contains mechanisms to review and adjust the policy as needed. 

The Court of Appeal accepted Gatwick's submissions that the SST "was entitled to rely upon his or her own policies, including the JZS, to deliver the purpose for which they had been designed, namely achieving the carbon budgets" [82], citing the case of Dawes. The SST here was entitled not to reduce the weight placed on the trajectories in the JZS. This was unchanged by two later pieces of information asserted by CAGNE as undermining that policy: 

1. submissions made into the examination by the Aviation Environment Federation seeking to undermine the JZS: the Court held that these were taken into account by the ExA and SST but that they rationally concluded the policy remained robust; and
2. a 'Policy Commission Return' prepared by the DfT for DESNZ in connection with the preparation of the Carbon Budget and Growth Delivery Plan: given the specific purpose of such returns, which are prepared periodically, it was rational for the SST not to take them into account so as to question the JZS – else she would have to take a whole sequence of such returns into account (given they are produced periodically), which would be unworkable. 

Requirement 'tailpieces'

The High Court and Court of Appeal also dismissed CAGNE's argument that the SST acted irrationally in accepting the wording of requirement 31 of the development consent order (DCO), which dealt with the mitigation of potential wastewater impacts by requiring Gatwick Airport and Thames Water (TW) to go through a process to confirm TW's capacity to take the increased wastewater flows from the expanded airport or otherwise for Gatwick to construct its own wastewater treatment works. 

Part of that ground challenged the common DCO drafting where a requirement imposes an obligation to be complied with in a particular manner "unless otherwise agreed" with the relevant entity overseeing that requirement (i.e. a local planning authority or other statutory body). A previous case (Midcounties Co-Operative) had found that such tailpieces could be unlawful where they allowed development to take place that went beyond the scope of development considered in the planning application (e.g. a limit on floorspace could be circumvented if "otherwise agreed" after permission was granted). However, the Court of Appeal concluded that that principle was not engaged in Gatwick's case, including because the DCO contained a provision requiring TW not to "otherwise agree" something unless it had no new or materially different environmental effects to those assessed in Gatwick's application. 

In response to CAGNE's assertion that it was not appropriate for TW as a statutory undertaker (rather than a local authority) to be able to approve a different course of action at all, the Court was content that this was acceptable given the matter was within their "statutory responsibilities" [97]. The tailpiece was perfectly lawful. 

This is a useful confirmation of the lawfulness of tailpiece drafting, provided it does not facilitate development that goes beyond that considered in the planning application. 

1. ^

   Now ISEP

Procedural takeaways

We have previously written on the Government's reforms to judicial review procedure for NSIP claims and have frequently said that we would need to wait and see whether they have the desired impact. In our view, the Gatwick claims are a useful indicator of the direction of travel, showing both the promise and some drawbacks of the reforms. 

Timings

Table 2 below shows the timings for the application and the legal challenges to the project. It took 27 months to get from application submission to grant of the DCO and 10 months to get from grant to a challenge-free consent. By comparison, from the grant of the Sizewell C DCO to the judgment of the Court of Appeal took around 17 months (albeit for Sizewell C permission to appeal was granted on the papers and there was a rolled-up hearing in the Court of Appeal instead of a permission hearing). The Court of Appeal stage for the Gatwick claims took just 5 weeks from appeal to judgment, including a 1.5 day oral hearing. The equivalent stage for the Sizewell C claim was almost 6 months!

This suggests that the target timescales introduced by Government in the revised CPR Practice Directions are encouraging judges to deal with NSIP cases swiftly and bump them to the front of the queue, particularly in the Court of Appeal. However, the target timescales can't solve everything – while there were only around 3 months from the filing of the Gatwick claims to the oral hearing in the High Court, it then took the judge a further 5 months to write up his judgment. There are no target timescales within which to give judgment and, even if a judge appreciates the need for speed (as Mould J seemingly did, by listing the oral hearing expeditiously), you can't rush a busy judge who is no doubt trying his best to appeal-proof his findings. 

Timings for the overall judicial review process will thus continue to remain somewhat unpredictable, with the potential to drag on longer than developers might like. And that is before the target timescales and procedural reforms are expanded beyond NSIPs to other planning decisions, as has recently been consulted upon by Government. 

Bar on appeals

Another major element of the Government's reforms was barring appeals to the Court of Appeal where claims are certified by the High Court as 'totally without merit'. We wrote in a previous article about the judicial review of the Stonestreet Green Solar DCO, in which we acted for the developer Interested Party, which was the first example of a claim being certified by a High Court judge as totally without merit and thus the claimant being unable to appeal to the Court of Appeal. 

We cautioned in that article that where NSIPs are more complex and impactful, and spawn challenges with more grounds, it is less likely that some or all grounds would be certified 'totally without merit', even if the grounds ultimately fail. That was the case in the Gatwick claims, where none of the grounds in either claim were certified 'totally without merit', and thus Mr Barclay appealed 2 of his 5 grounds and CAGNE appealed 4 of their 7. That is despite the Court of Appeal ultimately concluding that none of the grounds were even 'arguable' so as to warrant permission to appeal.

We have opined before that routes of judicial review should not be shut off arbitrarily lest we risk abandoning the proud English law tradition of the rule of law and the ability to question Government decision-making. Where High Court judges feel that grounds do not meet the threshold to be certified 'totally without merit', it is not necessarily wrong that a route of appeal should remain open. The important thing is that judges feel empowered to apply that certification where they truly believe grounds are entirely hopeless, enabling the very weakest arguments to be filtered out at an early stage. Other aspects of the reforms should be relied upon to swiftly dispose of grounds that are misdirected but which do not meet that high bar. 

Conclusion

The Court of Appeal's judgment marks the end of a long road to consent for Gatwick Airport. The decision, and that of the High Court before it, deals with a lot of controversial topics from the world of infrastructure planning, offering useful guidance as to lawful approaches and the scope of a decision-maker's discretion. The route to get to that judgment shows that the courts seemingly 'get the message' on timings – listings in the High Court and Court of Appeal were quick, and the Court of Appeal produced a detailed judgment in just a single week. 

But we are still in the early days of the procedural reforms. It remains to be seen whether things will get even better as the Court adapts to the unrelenting pace required by the revised Practice Directions or whether Government attempting to extend the benefits of those revisions to an ever wider pool of claim might dilute their effect. One thing is for sure – there will be plenty more NSIP judicial reviews by which to find out. 

Table 1: Grounds of challenge

Table 2: Timings for the application and legal challenges