Planning Appeals in London 2025: What to Do if Your Extension is Refused

Understanding the planning refusal decision: when a planning application is refused by a London local planning authority (LPA), the refusal notice must state the reasons for refusal — in plain language and with reference to the relevant local plan policies. Common reasons for refusal of house extensions and loft conversions in London: impact on the character and appearance of the area (the extension does not respect the prevailing scale, massing, or appearance of the surrounding area; the proposed dormer is too large or too prominent on the streetscene); overlooking and loss of privacy (the extension creates new windows or a roof terrace that overlooks a neighbouring property's garden or habitable rooms); overbearing impact/loss of light (the extension is too large in relation to the neighbouring property and will be overbearing or will cause unacceptable daylight or sunlight loss to a neighbouring window — assessed using the BRE Daylight and Sunlight methodology); designated area impact (the extension does not conserve or enhance the character or appearance of a conservation area or does not respect the character of a listed building; a heritage impact assessment has not been submitted or does not sufficiently address the impact); highway impact (proposed access, parking changes, or visibility splays do not meet the highways standards — less common for residential extensions); biodiversity and ecology (the extension affects a bat roost, swift nesting site, or other protected species without an adequate mitigation strategy — increasingly common in London extensions). Revise and resubmit vs appeal — when each is the right choice: revise and resubmit a new planning application: the right choice when the refusal reasons relate to design, scale, or massing issues that can be addressed by a design revision — reducing the proposed depth of a rear extension; lowering the ridge height of a loft conversion dormer; changing the cladding material or window proportions; setting back a side extension further from the boundary; introducing obscure glazing to resolve an overlooking concern. A revised application (free resubmission within 12 months of a refusal on a Householder application — confirmed under the Planning Practice Guidance) avoids the time, cost, and uncertainty of an appeal and is the quickest route to approval where design revisions can address the refusal reasons. Appeal (Section 78): the right choice when: the applicant believes the refusal is incorrect (the planning officer has misapplied the local plan policies; the reasons for refusal are inconsistent with recently decided similar appeals or permissions in the area; the LPA has applied excessive conservation area or heritage impact weight to a proposal that does not cause less than substantial harm under the NPPF); the applicant is unwilling to compromise on the design (the proposed extension is exactly what the project requires and any reduction in scale or change in design would make the project unviable); the refusal reasons are wholly or mainly policy-based (not design revision matters). Before deciding to appeal: review the refusal reasons carefully with a planning consultant or planning-experienced architect; consider whether a pre-application meeting with the LPA (where available) indicated that a revised scheme would be acceptable; check recent appeal decisions for the specific LPA and conservation area for comparable proposals (public search tool available on the PINS website — acp.planninginspectorate.gov.uk).

The three types of planning appeal under Section 78: Written Representations: the most common type of planning appeal — accounting for approximately 80% of all appeals. Both parties (appellant and LPA) submit written representations setting out their case; the Planning Inspector reads the representations, visits the site (an accompanied site visit with both parties, or an unaccompanied visit for straightforward cases), and issues a written Inspector's Decision. Written Representations are appropriate for: most householder extension and loft conversion appeals; cases where the issues are relatively straightforward and can be clearly argued in writing; where there are no complex legal or technical expert issues that require cross-examination. Written Representations timescale: currently approximately 20-28 weeks from appeal start to Inspector's Decision (as at 2025). Hearing: a Hearing is an informal round-table discussion before a Planning Inspector. Both parties can attend and speak (the LPA, the appellant, and any interested parties — typically neighbours — who have registered to participate). The Inspector chairs the discussion and directs the agenda. Hearings are appropriate for: appeals involving more complex policy issues where the Inspector wishes to question both parties; cases involving a number of issues that benefit from direct discussion. Hearing timescale: approximately 30-52 weeks from appeal start to hearing date and subsequent Inspector's Decision. Public Inquiry: the most formal type of appeal — equivalent to a court proceeding. Both parties typically have legal and expert (planning, heritage, acoustics, daylight/sunlight) representation; cross-examination of witnesses is allowed. Inquiries are appropriate for: major or complex appeals; cases involving significant heritage impacts; cases with multiple third-party objectors and complex technical evidence. Public Inquiry timescale: approximately 40-78 weeks from appeal start to close of Inquiry and Inspector's Decision. Note: very few householder extension and loft conversion appeals proceed to Hearing or Inquiry — Written Representations is the appropriate procedure for the vast majority of London residential extension appeals. The PINS appeal process — step by step (Written Representations): Step 1 — starting the appeal: the appellant submits an appeal form to PINS via the PINS Appeal a Planning Decision portal (www.gov.uk/appeal-planning-inspectorate) within the appeal deadline (see below); the appeal form requires: the application reference; the date of refusal (or date of non-determination — see below); the grounds of appeal (why the refusal is considered to be wrong); the appeal procedure requested (Written Representations, Hearing, or Inquiry). Appeal deadline: 12 weeks from the date of the refusal notice (for a Householder application — Class 3A appeals). If the appeal is submitted after this deadline, PINS will not accept it. Step 2 — questionnaire and representations: the LPA submits an appeal questionnaire (within 5 weeks of the appeal start); the appellant submits a full written statement of appeal (within 6 weeks of the appeal start); the LPA submits its written representations (within 6 weeks of the appeal start); interested parties (neighbours, councillors, etc.) have an opportunity to submit representations to PINS. Step 3 — Inspector's site visit and decision: the Inspector carries out a site visit; the Inspector issues the appeal decision (an Inspector's Decision letter) — within the PINS target timescale of 20-28 weeks from appeal start for Written Representations. The Inspector's Decision is final — it can only be challenged at the High Court on a point of law (Section 288 TCPA 1990) within 6 weeks of the decision. Non-determination appeal: if the LPA has not made a decision on a planning application within the statutory 8-week determination period (for a Householder application) and has not agreed an extension of time with the applicant, the applicant can appeal to PINS on grounds of non-determination. The appeal is treated as if the application has been refused. Non-determination appeals are uncommon but are a useful tool where an LPA has been significantly delayed or has used the delay to avoid making a formal refusal decision.

Planning appeal costs — appellant's costs: Written Representations appeal costs for a householder extension appeal in London (appellant side): planning consultant to draft the Statement of Appeal and manage the appeal process: £1,500-£4,000; architect to produce any additional drawings or design justification: £500-£2,500; planning consultant or solicitor for any additional legal argument: additional £500-£3,000 (where legal points are involved). Total typical appellant costs for a Written Representations householder appeal: £2,000-£6,000. Note: there is no fee payable to PINS for submitting a planning appeal (planning appeals are free to submit). Application for costs: a party can apply to PINS for an award of costs against the other party if the other party has acted unreasonably in the way it has conducted the appeal. Common grounds for costs: the LPA refused a planning application for reasons that are not supported by any adopted policy; the LPA refused an application without carrying out an adequate assessment; the LPA changed its reason for refusal during the appeal process; the LPA failed to comply with the timetable for the appeal (delayed questionnaire, late representations). An award of costs is made by the Inspector alongside (or separately from) the main appeal decision — the Inspector assesses whether the party applying for costs has been unreasonably prejudiced by the other party's conduct. Costs are not awarded routinely — the grounds must be well-evidenced and the conduct must genuinely have been unreasonable (not merely that the LPA refused a planning application). Planning appeal success rates for householder extension appeals: PINS publishes statistics on appeal outcomes. Nationally, approximately 30-40% of all planning appeals (across all appeal types) are allowed (granted) by Inspectors. For householder extension and loft conversion appeals specifically: the success rate varies significantly by LPA, by type of refusal reason, and by the quality of the appellant's case. Where the refusal reasons are purely design-related and the proposed design has been carefully justified by a planning consultant and architect, success rates are typically higher (approximately 40-60% for well-prepared householder appeals with good supporting evidence); where the refusal involves heritage impact, conservation area character, or complex daylight/sunlight issues, the success rate depends heavily on the quality of the heritage impact assessment or daylight/sunlight analysis submitted in support. The role of a planning consultant and architect in a London extension appeal: planning consultant: reviews the refusal reasons and assesses the strength of the appeal case; researches comparable appeal decisions and permissions in the same LPA and conservation area; drafts the Statement of Appeal (the main written argument to the Planning Inspector); responds to the LPA's questionnaire and representations; attends the site visit (accompanied) and any Hearing or Inquiry; applies for an award of costs where justified. Architect: produces any revised drawings, sections, or visual impact assessments required to support the appeal; undertakes daylight and sunlight analysis (BRE methodology — relevant for overbearing or daylight impact grounds); prepares design and access statement evidence for the appeal; may attend the site visit with the planning consultant. Pre-application engagement with the LPA before submitting a new application: most LPAs in London offer a pre-application advice service (typically £150-£500 for a householder pre-application advice meeting) — this allows the applicant to present a revised scheme before formally submitting a new application and to obtain the officer's view on whether the revisions address the refusal reasons.