The exceptions to inappropriate development in the Green Belt

Although the judgment in Abdul Sattar v The Secretary of State for Housing, Communities and Local Government & Anor [2026] EWHC 1825 (Admin) was handed down on 10 June, it has only recently been published.

The claim, brought under section 288 of the Town and Country Planning Act 1990, challenged a decision of a Planning Inspector, appointed by the Secretary of State, dismissing an appeal against the Royal Borough of Windsor and Maidenhead's refusal of retrospective planning permission for a roof extension and alterations to a garage at a property within the Green Belt. The Inspector concluded that the proposal constituted inappropriate development, resulting in a loss of Green Belt openness that was not justified by very special circumstances.

The claimant advanced three grounds:

1. that the Inspector wrongly excluded consideration of Green Belt openness and purposes when assessing proportionality under paragraph 154(c) of the National Planning Policy Framework;
2. that the Inspector failed properly to weigh harm to the Green Belt against the scheme's benefits; and
3. that the Inspector gave inadequate reasons, particularly regarding paragraph 154(g).

HHJ Karen Walden-Smith, sitting as a High Court Judge, rejected all three grounds.

On Ground 1(a), the Court held that the distinction between appropriate and inappropriate development under paragraph 154 is a matter of policy, distinct from the separate question of harm to Green Belt openness and purposes, applying the Court of Appeal's approach in R (Lee Valley Regional Park Authority) v Epping Forest DC. The Court found that the Inspector had not shut his mind to the impact on openness, noting that The Inspector had expressly referred to the increase in visual bulk caused by the reconfiguration of the roof and addition of dormers, and had acknowledged that floor area was not the only relevant metric. On Ground 1(b), the judge rejected the claimant's contention that the Inspector could not properly conduct the very special circumstances balancing exercise without first quantifying the level of harm, holding that it was sufficient for the Inspector to conclude that the high threshold for very special circumstances had not been met without specifying the precise weight attached to the harm.

On Ground 2, the judge held that whether the development amounted to partial redevelopment for the purposes of paragraph 154(g) was a matter of planning judgment properly resolved by the Inspector's finding that the proposal did not involve partial or complete redevelopment, and that, absent any substantive argument to the contrary from the claimant, the Inspector was not required to give further reasons or "reasons for reasons".

On Ground 3, the judge concluded that the Decision Letter met the standard required by established authority, including South Bucks v Porter and Clarke Homes, leaving no room for genuine doubt as to what had been decided and why.

Accordingly, the section 288 challenge failed in its entirety, and the Inspector's original decision to dismiss the planning appeal stands.

Ben Fullbrook is a barrister at Landmark Chambers. He represented the Secretary of State, instructed by the Government Legal Department.