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EIA Quality Mark: Dennis and EIA, but what about the Bash Street Kids?


This article considers the implications for EIA and the preparation of Environmental Statements (ESs) of a High Court decision that rules planning permissions cannot be split retrospectively, making it difficult to modify large schemes and what this means for preparing new applications. 

The High Court Judgement Dennis V LB Southwark

There has been much attention of late on the issue of severability (or not) of extant planning permissions which has been brought to the fore by the case of Dennis v LB Southwark [2024] EWHC 57 (Admin) (https://www.bailii.org/ew/cases/EWHC/Admin/2024/57.html) and builds on the principles established by the Pilkington and Hillside cases.  Pilkington established that where two or more planning permissions have been granted on the same area of land and development has been carried out under one of those permissions, if that development has made it physically impossible to carry out development approved by another consent then that consent may no longer be relied upon.  In Hillside, the Supreme Court approved the Pilkington principle and developed matters further by leaving the option open for ‘severable’ consents where there is ‘clear contrary intention’ that the planning consent should not be treated as a single integral scheme.

In this case the claimant (Aysen Dennis, a local resident) made an application for Judicial Review against a decision by Southwark Council to grant an s.96A non-material amendment to an Outline Planning Permission for a large, phased estate regeneration (to allow part of the site to be developed at a higher density then which had been permitted).  The NMA sought to insert the word ‘severable’ into the description of development permitted by the extant planning permission which, in the view of the LPA, was considered to fall within the remit of a s96a application as the phased and outline nature of the permission was sufficient to demonstrate severability.

In reaching judgement, Mr Justice Holgate disagreed with the LPA in that there was no clear indication that the planning permission was severable, having regard to how the proposals were assessed in the supporting documentation (Design & Access Statement, Environmental Statement etc) and the officers report to Committee, rather it was a single permission with provisions for phasing.  As such were it to be severed it would therefore significantly enlarge the ‘bundle of rights’ granted by that permission which would constitute a ‘material’ amendment.  Furthermore, Holgate added that “..…I have strong reservations in any event about the legality of an amendment to a planning permission which simply inserts language as uncertain as the bare term "severable". There was nothing to indicate the extent to which the OPP was purportedly severed. For a large-scale development it would have been possible to conceive of many different alternatives”.  

What is a severable permission?

In essence, for a permission to be severable it would, in practical terms, need to comprise of a series of ‘mini-permissions’ that could be amended by way of a ‘slot in’ application changing that part of the development (either quantum or use) whilst ensuring that the remainder of the permission was able to be implemented as per the original consent (consistent with the principles established by Pilkington and Hillside).

How to demonstrate an application is severable?

In order to demonstrate that a scheme as a whole is severable then it will be important that the associated assessment work is prepared on this basis, in respect to what parts of the scheme are severable (i.e. the different phases of the development) and the implications were this to be the case (with clarity on the parameters of any alternative form of development being provided).

With this in mind, and having specific regard to preparation of Environmental Statements to support outline planning applications in particular, given that Dennis has closed off the opportunity to use s96a applications (as well as S73’s and new ‘slot in’ permissions) to retrospectively achieve the severability of existing permissions then it does becomes important that at the initial assessment stage the implications of the severability of large scale proposals are properly identified and presented in a way that these can be easily understood by the decision maker (and any third party).  

What does this mean for ES preparation?

In ES terms this is likely to necessitate the need for individual chapters to assess parts of the scheme being delivered individually and/or as a whole to demonstrate severability and by doing that any interrelationship between different parts of the development is assessed and understood, for example the impacts on the delivery of any associated infrastructure.  In addition, the cumulative impacts part of the document would need to be multifaceted to cover both parts of the site being delivered together with other relevant schemes in the local area. 

The challenge to this will be to present the ES as a clear and concise assessment that identifies the impacts of each part of the scheme (and associated mitigation required and residual impacts for each potential severable part) which could be no small feat given the large scale nature of proposals typically covered by ESs. 

This points to the need for a clear brief at the project outset to identify how the proposals could be potentially severable and close working with the project team to ensure that there is consistency across how this is assessed within individual ES technical chapters and in particular the cumulative impact assessment as it is likely to be necessary to test different scenarios within set parameters (as it will be necessary to provide a clear indication on the extent of variations that may come forward in the future).  This assessment work will also need to be consistent with other associated documentation accompanying the planning application.  This approach is likely to broaden the role of the ES and its size and so it is important that the introductory chapters (most notably the design alternatives) clearly signpost the intent that the resulting permission would be severable (and where).

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