Non-material amendment that allowed ‘drop in’ phases in Aylesbury Estate regeneration was ultra vires, High Court rules

A High Court judge has found that Southwark Council's non-material amendment to a historic outline planning permission (OPP) for the Aylesbury housing estate, which added the word 'severable' to the OPP, was ultra vires.

In his decision in Dennis, R (On the Application Of) v London Borough of Southwark [2024] EWHC 57 (Admin), Mr Justice Holgate said Southwark's submissions regarding severability "lacked coherence".

The south London estate, which became one of Europe’s largest housing estates when it was built in the 1970s, has been earmarked by the council for demolition and redevelopment since 2005.

As part of redevelopment efforts, the council granted OPP in 2015 for the creation of a new neighbourhood over a 15- to 20-year period and an increase in the number of dwellings to more than 4,000 houses and flats.

Central to the legal dispute was a council planning officer's decision to approve a section 96A of the Town and Country Planning Act 1990 non-material amendment under delegated powers in March 2023 that inserted the word "severable" into the description of the OPP.

According to the Public Law Interest Centre, which represented the claimant, the amendment made it easier for developer Notting Hill Genesis to 'mix and match' new planning permissions across the estate differing from the original masterplan, which was formed in consultation with residents.

At the High Court, Holgate J considered arguments from the council that said the OPP was already severable and the s.96A amendment was only intended to confirm this in express terms.

The claimant meanwhile argued that it was not severable as the permission was not granted on a ‘mix and match’ basis, which would allow the developer to implement another permission so as to ‘drop in’ a phase physically incompatible with the OPP and yet still be able to rely upon the OPP for later phases.

They also submitted that the purpose and effect of adding the word 'severable' was to change the rights granted by the OPP.

In handing down his decision, Holgate J said: "I am in no doubt that on a true construction the OPP was not severable prior to the s.96A amendment. It was a single planning permission with provisions for phasing.

"To the extent that the amendment made on 28 March 2023 severed the OPP, it had the effect of disapplying the Pilkington principle, i.e. it made it unnecessary to apply the physical impossibility test to a future 'material' departure from the development authorised by the grant of the OPP. It therefore significantly enlarged the bundle of rights granted by that permission."

He added: "In these circumstances, I agree with the parties that it must follow that this was a 'material' amendment of the OPP for the purposes of s.96A of the TCPA 1990. Accordingly, Southwark's decision dated 28 March 2023 was ultra vires that provision."

He said that on this basis, the claim must be allowed. Although the judge said he had "strong reservations" about the legality of an amendment to a planning permission which "simply inserts language as uncertain as the bare term 'severable'".

He said there was "nothing to indicate" the extent to which the OPP was purportedly severed and that, for a large-scale development, it would have been possible to conceive of many different alternatives.

Barristers at Landmark Chambers appeared for both sides in the judicial review.

Melissa Murphy KC and Heather Sargent, both of Landmark Chambers, appeared for Southwark, instructed by Sadia Hussain.

Jenny Wigley KC and Alex Shattock, also of Landmark Chambers, appeared for the claimant, instructed by Alexandra Goldenberg and Saskia O'Hara at the Public Interest Law Centre.

A statement detailing the case on Landmark Chambers's website said Holgate J's judgment "suggests that phasing arrangements or a phasing plan may be insufficient to demonstrate severability, even in the context of a large outline scheme".

It also said the case has significant implications for existing and future schemes where 'drop-in permissions' have or are proposed to be used.

Adam Carey