- Decision
- allowed, 3 September 2026
- Decided by
- Planning Inspector: SE Hughes
- Authority
- Buckinghamshire (South East)
- Appeal reference
- 6005649
- Application reference
- PL/25/2357/FA
- Procedure
- written representations
- Development
- Demolition of side extension and conservatory; single-storey rear and side extensions (non-determination appeal)
- Site context
- green belt, national landscape
- Green Belt
- Yes
- Framework applied
- August 2026 NPPF
- Determinative policies
- GB7(1)(b)
- Development plan policies
- Wycombe District Local Plan 2019 DM43, DM34
- Main issues
- inappropriate development
Summary
A non-determination appeal to replace an elongated side extension and conservatory with compact single-storey extensions, at a house already extended beyond the local 50% volume allowance. Allowed. There was no net volume increase and the form was more compact, so despite a "technical conflict" with Wycombe DM43 the additions were not disproportionate under GB7(1)(b).
Issues and findings
- Transition. "the policies pertinent to this appeal, including those relating to the extension and alteration of buildings in the Green Belt remain unchanged, except for their regrouping under policy GB7 and renumbering. Therefore, there is no need to invite further comments" (DL ¶4).
- GB7(1)(b): PASS. "whilst I am mindful of the technical conflict with Policy DM43 … and the exceedance of the 50% allowance, as the Framework does not define 'disproportionate' additions, and since, in relative terms, the dwelling would not be larger volumetrically than the existing dwelling, I find that it would not result in disproportionate additions to the original building" (DL ¶13).
Planning balance
No VSC needed. Conflict with the development plan (DM43) was outweighed by the Framework as a material consideration (DL ¶17).
What made the difference
Volume neutrality plus a more compact form. The Inspector effectively allowed the "existing" building to be the practical comparator for a like-for-like swap of past extensions, even though GB7(1)(b) is framed against the original building.
Transferable points
- Replacing existing extensions with no net volume gain and a more compact form can be "not disproportionate" even where the total exceeds a local % cap (DL ¶13).
- Local numerical caps (DM43 50%) are consistent with the Framework but not decisive, because "disproportionate" is undefined nationally (DL ¶¶8, 13).
- Inspectors are treating the GB7(1)(b) extension wording as unchanged from 2024 §154(c) (DL ¶4).
Policy findings
Policy codes are those of the National Planning Policy Framework (August 2026) unless a development plan is named.
| Policy | Finding | Weight | Note |
|---|---|---|---|
| GB7(1)(b) | pass | original + previous extensions already exceed DM43's 50% allowance, but the proposal does not increase existing volume and is more compact → not disproportionate (DL 10-14) | |
| Wycombe DM43 | conflict | technical conflict with 50% volume allowance; outweighed because the Framework does not define disproportionate (DL 13, 17) | |
| N4 | neutral | no effect on Chilterns National Landscape (DL 15) |
Key facts
- Original dwelling c.607-706 m3; existing extensions c.492-591 m3, over the 50% allowance
- Proposal removes c.310 m3 and adds c.308 m3 (appellant's survey); Council says net decrease of 32 m3
- Council said it would have approved had it decided the application
- Inspector found GB7 extension policy "unchanged" except renumbering, so did not consult on the new Framework
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.