The fallout from Hillside has continued in the courts.

The UK Supreme Court judgment on Hillside Parks Limited v Snowdonia National Park Authority in late 2022 attracted significant attention among planning professionals. Hillside considered the Pilkington principle, which deals with the situation whereby development on a land area approved under one planning permission makes it physically impossible to carry out development approved under another permission. The judgment resolved that planning permission for multi-unit developments is usually granted as an integral whole, with severability only being applicable in specific contexts.

A recent high court judgment (Aysen Dennis v London Borough of Southwark) from Mr Justice Holgate in January 2024 has directly tackled this severability point. The ruling is likely to have implications for practitioners, particularly those involved in large multi-phase schemes and “drop-in” applications.

Background

In August 2015, the London Borough of Southwark granted outline permission for the regeneration of the Aylesbury Estate in south-east London, divided into phases. Phase 2A was built between 2020 and 2023. In July 2022, the developer, Notting Hill Genesis, submitted a “drop-in” detailed application for Phase 2B, proposing development which fell outside the outline parameters. In January 2023, the Planning Committee resolved to grant Phase 2B, contingent upon a Section 96A application to formalise the outline permission’s “severable nature”. The Section 96A application proposed adding the word "severable" to the outline permission description, and in March 2023, this amendment was approved, being deemed non-material.

The claimant (a local resident) argued this was a "material" change, exceeding the scope of Section 96A, and the original outline permission was not severable. The defendant (LB Southwark) contended that it was inherently severable, particularly due to its phasing provisions, and thus the developer could progress a phase under a “drop-in” permission without affecting their right to implement further phases under the outline permission. Therefore, the core issue was whether the outline permission’s conferred rights were materially changed by the Section 96A amendment, and what "severable" means in this context.

The judgment

The question of severability was considered in the context of the Hillside case and the application of the Pilkington principle, which referred to severance in the sense of disaggregation, with Mr Justice Holgate finding, “Nothing less than severance into discrete permissions would have sufficed for the developer’s argument to succeed in the Supreme Court.” Furthermore, the court considered that the Pilkington principle applies to both detailed and outline permissions, and that including phasing in an outline permission does not inherently imply severability.

In considering the implications if one were to accept that phasing was sufficient to sever a permission, thus circumventing the Pilkington principle, Mr Justice Holgate highlighted potential unintended consequences, including the application of statutory time limits for the implementation of each separate permission, noting:

Applying this reasoning to the case, the phasing allowed for in the outline permission was considered compatible with a single indivisible planning permission, and did not therefore inherently indicate multiple separate permissions. The judgment found there was no clear indication that the outline permission was severable before the Section 96A amendment. The officer’s report and other relevant documents considered several factors for the proposed development as a whole, including phasing, infrastructure, and benefits, and did not suggest that individual phases might later be replaced by materially different “drop-in” applications, nor was this considered within the Environmental Statement. Therefore, the Section 96A amendment, which severed the outline permission, significantly enlarged the bundle of rights granted by the permission, rendering the decision ultra vires, and was therefore quashed. In his concluding remarks, Mr Justice Holgate cautioned:

Implications

This case underscores the ongoing implications of the Hillside judgment for planning practitioners, particularly those involved in multi-phased schemes and “drop-in” applications. It provides a warning that it is likely insufficient to rely on a phasing plan, or the word “severable” within the description of the development, to demonstrate severability. The judgment indicates that greater consideration needs to be given at the application preparation and decision-making stages to ensure such a permission is inherently severable, and not just described as such, if the intention is to allow for the possibility of disapplying the Pilkington principle in the future.

The judgment may be viewed here.

Further information

Contact Ciaran Hagan