Maisie Cottage, Bottrells Lane, Chalfont St Giles (stable to dwelling)

appeal 6011889·Buckinghamshire·25 September 2026dismissed
Decision
dismissed, 25 September 2026
Decided by
Planning Inspector: A O'Neill
Authority
Buckinghamshire (South East)
Appeal reference
6011889
Application reference
PL/25/4593/FA
Procedure
written representations
Development
Conversion and single-storey side extension of a stable building to a one-bedroom dwelling, with a new garden, gravel driveway and boundary hedging
Homes
1
Site context
green belt, national landscape, open countryside, rural lane
Green Belt
Yes (grey belt not argued)
Framework applied
August 2026 NPPF
Determinative policies
GB6(2), GB7(1)(f)(iii), N4
Development plan policies
Chiltern District Local Plan 1997 GB2, GB11, LSQ1, Core Strategy for Chiltern District 2011 CS22
Main issues
whether inappropriate development in the Green Belt and effect on openness; Chilterns National Landscape; very special circumstances

Summary

Conversion and extension of a stable to a one-bedroom dwelling in the Green Belt and the Chilterns National Landscape was dismissed, for the third time on this site. The building works fell within GB7(1)(b). The new garden and driveway did not: they were a change of use of open grassland to residential use, which no GB7 exception covers. That made the proposal inappropriate development, and one dwelling with a modest biodiversity gain did not amount to very special circumstances.

Issues and findings

Planning balance

GB6(2) very special circumstances. Harm: inappropriateness and loss of openness (substantial weight) and failure to conserve the National Landscape (substantial weight under N4). Other considerations: one home (substantial weight under HO7, though the benefit is called limited) and biodiversity net gain (moderate). These "are consequently not considerations that clearly outweigh the harm arising from inappropriateness and other harm" (DL ¶23).

What made the difference

The garden. The conversion on its own was not inappropriate, but a dwelling needs a curtilage, and enclosing open grassland as garden and drive is a residential change of use that GB7 does not cover. Making the garden as small as possible did not help: the issue was the category, not the size. Grey belt under GB7(1)(g) was not argued. A scheme whose curtilage stayed within land already in the building's use, or a successful grey belt case, would have been needed.

Transferable points

Policy findings

Policy codes are those of the National Planning Policy Framework (August 2026) unless a development plan is named.

PolicyFindingWeightNote
GB7(1)(b)passconversion and extension of the stable agreed to fall within the exception; inspector saw no reason to differ (DL 5)
GB7(1)(f)(iii)failnew garden and driveway are a change of use of undeveloped grassland to residential use; residential uses are outside the material-change-of-use exception (RB Kingston upon Thames v SSLUHC [2023] EWHC 2055 (Admin)); no other exception applies; the letter writes "GB7(f)(iii)" (DL 6-7)
GB6(2)harmsubstantialinappropriate development; domestic paraphernalia and parking would fail to preserve openness in spatial and visual terms; a 2024 inspector had called the effect of a similar curtilage limited but harmful (DL 8-12, 22-23)
GB6(2)failvery special circumstances do not exist; one dwelling and biodiversity gain do not clearly outweigh the harm (DL 23)
N4conflictsubstantialChilterns National Landscape; domestication of the land erodes rural character; overall magnitude of harm limited because the site is small; substantial weight to conserving and enhancing natural beauty (DL 13, 17-19, 23)
Transitional(2)conflictvery-limitedLocal Plan GB11 (residential reuse of Green Belt buildings, subject to criteria) is more restrictive than the Framework; very limited weight under Annex A paragraph 2; conflict with GB2 and GB11 is still recorded at DL 12 (DL 4, 12)
S5(1)(j)not-engagedsupply shortfall acknowledged, but S5(5) means S5 does not apply in the Green Belt (DL 23)
HO7benefitsubstantialone dwelling; contribution described as limited, but given substantial weight in light of the supply position and HO7 (DL 20, 23)
N2 (BNG)benefitmoderateappropriate provision for biodiversity net gain, of modest scale; overcomes a reason for the 2025 dismissal (DL 21)

Key facts

Sources

This note is one of the decisions behind the NPPF 2026 Navigator, which shows how each Framework test has been applied across all the decisions in the database. Also available as Markdown.