The King on the application of Wildfish v Buckinghamshire Council

Hearing dates: 14 – 16 October 2025

Approved Judgment

This judgment was handed down remotely at 11am on 20 November 2025 by circulation to the parties or their representatives by e-mail and by release to the National Archives.

In both these claims, the Claimants — “Wildfish” and “Wood” — seek judicial review of the decision, dated 4 March 2025, by the Defendant (“the Council”) to approve an application for the grant of reserved matters approval (“RMA”) and discharge of conditions 8 and 22 in respect of an outline planning permission (“OPP”), granted on 24 March 2022, with a further varied permission granted on 10 December 2024, for a residential development near Maids Moreton, Buckinghamshire (“the Site”).

Wildfish is an environmental charity that campaigns to protect rivers and streams in the United Kingdom from pollution and over-abstraction. Ms Wood is a local resident who has objected to the development, both in her personal capacity, and as an active member of the Maids Moreton and Foscote Action Group. Their claims have been linked for case management and hearing because they challenge the same decision.

The First Interested Party (“IP1”) is the applicant for planning permission. The Second Interested Party (“Anglian”) is the water authority for the area in which the development is situated. Anglian has played no part in these proceedings.

The grounds of challenge in the Wildfish claim may be summarised as follows:

i) Ground 1: error of law in approving a substantial alteration to the application for RMA after expiry of the time limit, and failure to consult on the application.

ii) Ground 2: error of law in approving reserved matters “as varied by” the permission granted under section 73 Town and Country Planning Act 1990 (“TCPA 1990”) on 10 December 2024 (“the section 73 permission”).

iii) Ground 3: the planning officer's report (“OR”) was significantly misleading; irrational; insufficiently investigated; failed to refer to material considerations; and it was inadequately reasoned. The Ofwat email dated 27 January 2025 was not listed as a background paper, as required by section 100D Local Government Act 1972 (“LGA 1972”).

iv) Ground 4: error of law in deciding not to re-consider the screening decision under the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 (“EIA Regulations 2011”).

The grounds of challenge in the Wood claim may be summarised as follows:

i) Ground 1: the decision to discharge condition 22 was ultra vires and irrational because the Defra 2.0 BNG metric and guidance was not used when calculating biodiversity net gain.

ii) Ground 2: the OR misled Committee Members on the calculations for measuring biodiversity net gain, did not investigate sufficiently, did not refer to material considerations and gave inadequate reasons. Alternative calculations, presented on behalf of objectors by Professor Shreeve, were not listed as background papers, in breach of LGA 1972.

iii) Ground 3: error of law in accepting the October 2024 resubmission of reserved matters out of time.

On 23 May 2025, I granted permission, on the papers, to apply for judicial review in both claims.

Planning history: Wildfish

EIA screening

On 24 November 2015, Aylesbury Vale District Council issued a negative screening opinion in respect of the proposed development under the EIA Regulations 2011.

The OPP

IP1 applied for OPP on 20 January 2016. The Council granted outline planning permission, on 24 March 2022, for up to 170 dwellings and associated infrastructure, at land off Walnut Drive and Foscote Road, Maids Moreton, Buckinghamshire MK18 1QQ (application ref 16/00151/AOP).

Condition 1 provided:

“Details of the appearance, landscaping, layout and scale, (hereinafter called “the reserved matters”) shall be submitted to and approved in writing by the Local Planning Authority before any development begins and the development should be carried out as approved.

Reason: The application is for outline planning permission.”

Condition 2 required application for approval of reserved matters to be made to the Council the local planning authority “no later than eighteen months from the date of this permission”. That time limit expired on 24 September 2023.

Condition 13 provided:

“The details to be submitted for approval in writing by the Local Planning Authority in accordance with Condition (1) above shall include a foul water drainage scheme for the site. The scheme shall include a waste water treatment capacity assessment to identify the need for any infrastructure upgrades and a programme for carrying out the works to inform site delivery.

No part of the development shall be occupied until confirmation has been provided to the local planning authority that the scheme and programming of any wastewater upgrades required to accommodate the additional flows from the development have been agreed with Anglian Water; and all wastewater upgrades required to accommodate the additional flows have been completed. The development shall be carried out in accordance with the approved details.

Reason: Network reinforcement works are likely to be required to accommodate the proposed development. Any reinforcement works identified will be necessary in order to avoid sewage flooding and/or potential pollution incidents in accordance with policy I5 and D-MMO006 of the Vale of Aylesbury Local Plan and the National Planning Policy Framework.”

Condition 22 provided:

“Prior to commencement of development updated Biodiversity Net Gain Calculations must be submitted and be approved in writing by the local planning authority, alongside the Ecological Mitigation, Compensation and Enhancement Plan and the Landscape and Ecology Management Plan. The calculations must be undertaken using the Defra 2 metric and guidance and result in a net gain in both habitat and hedgerow units of at least 10% having regard to net gain being delivered across the overall development site.

Reason: To comply with the requirements of Policies D-MMO006 and NE1 of the Vale of Aylesbury Local Plan and the NPPF.”

Previous judicial review claim

A member of the Maids Moreton and Foscote Action Group applied unsuccessfully for judicial review of the grant of OPP on multiple grounds, including an alleged failure to review the EIA screening decision. The claim was dismissed on 16 November 2022 by Cranston J. in R (Hardcastle) v Buckinghamshire Council [2022] EWHC 2905 (Admin).

RMA applications

IP1 made its RMA application on 25 May 2023 (23/01636/ADP) for 163 dwellings, in the following terms:

“Reserved matters being sought for appearance, landscaping, layout and scale for 163 dwellings on land off Walnut Drive and Foscote Road and discharge of condition 22 (biodiversity net gain) and condition 8 (CMP) of outline approval 16/00151/AOP).”

A second duplicate application was submitted on 18 September 2023. The second application has not been determined. There was no application for discharge of condition 13.

On 16 October 2023 a new set of plans and documents were submitted by IP1 together with a new site notice, appearing to correct errors in the initial RMA application documents. The number of dwellings remained 163.

On 29 March 2024 a new application form was submitted with a further new set of plans and documents, though this time no new site notice was posted. The number of dwellings remained 163.

On 17 October 2024, IP1 submitted a further new set of documents, described as an “amended planning application pack”. A new site notice was provided. It reduced the number of dwellings from 163 to 153 and made various other changes which are considered under Ground 3 of the Wood claim.

Communications on drainage in 2023 & 2024

In an updating email, on 12 June 2023, IP1 informed the Council that the required drainage capacity statement was not yet available as it required input from Anglian. This was usually done “at S104 stage” 1.

On 13 September 2023, IP1's drainage consultant informed IP1 by email that Anglian had confirmed a suitable connection point to the main sewer and stated:

“Anglian Water has assessed the impact of a pumped conveyance from the planning development to the public foul sewerage network and we can confirm that this connection is acceptable as the foul sewerage system, at present, has available capacity for your site…..

A full programme of works will be issued upon S104 consultation with Anglian Water …..”

On 3 July 2024, an email was sent by Anglian to the Council which stated:

“Our response stating the drainage strategy is acceptable to us relates to the local foul network, it does not relate to the receiving water recycling centre (WRC), which...