21 October 2019


The appellant, Gladman, submitted planning applications for two housing sites in Kent. These were refused and unsuccessfully appealed. The Court of Appeal, in Gladman Developments Ltd v Secretary of State for Communities and Local Government and others [2019] EWCA Civ 1543, upheld the planning inspector’s decision. It found no issue with the assessment that Gladman had not taken sufficient steps to tackle air quality issues arising from the proposed development.

What was the proposal and why was it in dispute?

Gladman applied for permission for two schemes totalling 470 homes and 120 extra care units. The local planning authority, Swale Borough Council, failed to determine the applications. At appeal, the inspector concluded that it was likely the developments would have an adverse impact on local air quality and the mitigation measures proposed were not sufficient to outweigh the negative effects. He dismissed the appeals.

In the course of appealing this to the High Court and then the Court of Appeal, Gladman raised several concerns. Of particular note to local planning authorities and developers, Gladman argued that the inspector had:

  • inadequately considered the mitigation measures proposed
  • failed to properly consider the use of a ‘Grampian’ condition, which could have addressed the issues
  • failed to properly take account of a relevant High Court decision
  • failed to properly take account of paragraph 122 of the 2012 National Planning Policy Framework (NPPF).

The court rejected each of the grounds and we have set out the key details in relation to each of these below.

Mitigation measures

Gladman had proposed mitigation measures, in the form of a financial contribution to mitigate the adverse impacts of the proposal on the local air quality. This had been calculated in line with the government approved methodology. The unilateral undertaking (which still had to be approved by the local authority) set out a scheme which included electric vehicle charging points for each dwelling, green travel measures and incentives to encourage walking, cycling, the use of public transport and electric or low emission vehicles. 

However, the inspector concluded that no evidence had been provided to show how effective those measures were likely to be in reducing the use of private petrol and diesel vehicles and forecast nitrogen dioxide emissions. The court agreed, highlighting that it was not the methodology at issue, but Gladman’s failure to demonstrate how the mitigation proposed would translate into meaningful reduction in pollution. The inspector was within his rights to reach the conclusion he did.

A Grampian condition

Gladman attempted to persuade the court that the inspector should have suggested a ‘Grampian’ condition i.e. granted permission but making the development conditional on first providing effective air quality mitigation measures. The court disagreed. The inspector was not under a duty to propose a Grampian condition which had not already been suggested to him. In this case, Gladman had been given ample opportunities (during the planning application and appeal stages) to suggest conditions but had not done so.

ClientEarth (No.2)

The case of ClientEarth (No.2) v Secretary of State for the Environment, Food and Rural Affairs [2016] EWHC 2740 (Admin) was being decided at the same time as the Gladman inquiry. In that case, the High Court held that the UK government should be implementing policies to ensure the UK complied with the Air Quality Directive 2008 at the earliest possible date. Gladman argued that the inspector should have assumed the local air quality plan would be consequentially amended to reduce air pollution in the local area and should have assessed the development against the future (improved) conditions. However, the Court of Appeal saw it as beyond the inspector’s remit to hypothesise about when and how the government would make the necessary changes to air quality standards. The inspector had appropriately considered the ClientEarth (No.2) judgment.

Paragraph 122 of the NPPF

Paragraph 122 of the NPPF (2012) stated that it is not for the planning regime to stray into other permitting and consenting regimes with the purpose of controlling pollution (a point now set out in paragraph 183 of the revised NPPF (2019)). This is to avoid duplication of efforts as planning authorities should rely on other agencies playing their part and properly policing pollution. Gladman stated that by making a decision based on air quality concerns, the inspector had strayed into another regime. The Court disagreed. It found there was, in the case of Gladman’s housing proposals, in fact no ‘air quality regime’. There was no established permitting system and control body in this context. As such, the inspector was within his rights to make air quality a deciding factor in the case. The court also pointed out that paragraph 124 of the NPPF specifically states that local air quality plans should be considered when making planning decisions (now reflected in paragraph 181 of the revised NPPF).

What are the key takeaways?

Developers should make, and local planning authorities should look for, clear links between any mitigation proposed and the reduction in adverse effects a development is to have. Any necessary mitigation proposed in the application should be secured through the planning process – whether it be in the design of the proposal, by a condition or a planning obligation. Where air quality is not dealt with by the environmental permitting regime, developers should expect the issue to be dealt with in the planning process and address it appropriately. If the extent of (any) impacts of a development are uncertain at the time of making a planning application, the use of Grampian conditions could be explored in order to enable the permission to be granted and the details finalised at a later stage.

For advice or further information on securing mitigation in planning applications, please contact either Gary Soloman or Sarah Sutherland.

Key contact

Gary Soloman

Gary Soloman Partner

  • Head of Planning and Compulsory Purchase
  • Regeneration and Highways
  • Compulsory Purchase and Compensation

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