Your extension was refused. Should you appeal? 34% success rate for householder appeals, 10-16 week timelines, costs from £0-£5k+. When appeals work and when they don't.
Success Rate: 34% for householder appeals (extensions) in 2024/25
Timeline: 10 weeks (householder written) to 16 weeks (all householder appeals)
Cost Range: £0 (DIY written) to £5,000+ (consultant-led hearing)
Best For: Clear policy support but council made errors in assessment
Worst For: Genuine design/amenity issues, conservation area refusals
No Appeal Fee: Planning Inspectorate charges nothing to lodge appeal
Your extension planning application was refused by your London borough. Before you accept defeat or redesign, understanding the appeals process could save your project.
According to the Planning Inspectorate's January 2025 statistics, householder appeals (which include home extensions) had a 34% success rate in 2024/25. That's better odds than many homeowners realize.
Based on data from Appeal Finder's success rate analysis, these scenarios have higher success rates:
Example: Council refused 4m rear extension claiming overdevelopment, but local plan policy clearly allows up to 6m for your house type. Strong appeal case.
Example: Three identical rear extensions approved on your street in past 2 years, but yours refused. Consistency argument works well.
Example: Refused due to privacy concerns, but your extension is 20m from nearest window and meets all separation distances. Inspector can override unreasonable objections.
Example: Planning officer recommended approval but committee refused on subjective grounds. Inspector may agree with professional assessment.
Example: Two-storey side extension with windows 8m from neighbor's windows. If council correctly applied policy, inspector will uphold refusal.
Example: Modern flat-roof extension in Victorian conservation area. Design subjective assessments rarely overturned.
Example: Proposing 8m rear extension where policy allows maximum 6m. Appeals won't override clear policy limits.
Example: Refused for sunlight/daylight impacts, but you can't provide daylight study to prove otherwise. Evidence gaps hard to overcome.
Householder appeals: 12 weeks from decision notice date
Miss the deadline and you cannot appeal. No exceptions.
Read the decision notice carefully. What are the exact reasons?
Can you address them with evidence, or did council misapply policy?
Register at Planning Inspectorate: acp.planninginspectorate.gov.uk
No fee required. Select "householder appeal" for extensions.
Address each refusal reason directly with evidence
Include: photos, drawings, comparable approvals, policy references
Keep under 1,000 words for householder appeals (inspector guidance)
Inspector will visit your property (unaccompanied for most householder appeals)
Ensure site is accessible and any key views are visible
10 weeks from validation for householder written representations
Decision is final (except judicial review on legal grounds - rare and expensive)
| Scenario | Appeal Route | Professional Cost | Success Rate |
|---|---|---|---|
| DIY written appeal (simple case) | Written Rep | £0 | 29% |
| Planning consultant statement | Written Rep | £1,500-3,000 | 29% |
| Consultant + hearing attendance | Hearing | £2,500-5,000 | 59% |
| Additional technical evidence (daylight study, etc) | Any | £500-2,000 | - |
Important: There is no filing fee for planning appeals. According to GOV.UK guidance on appeal costs, all parties normally pay their own expenses. You only risk paying the council's costs if you behave unreasonably during the process (missing deadlines, providing false information, etc).
Some London boroughs have lower appeal success rates than others, indicating stricter planning enforcement or better-drafted refusals. According to Appeal Finder's local authority data, council success in defending refusals varies significantly.
If your borough typically loses appeals (low council success rate), it may indicate:
If your borough wins most appeals (high council success rate):
When: Refusal reasons identify specific design issues you can fix
Timeline: 8-13 weeks for new decision (faster than appeal)
Cost: No new planning fee if resubmitted within 12 months
When: Unclear why you were refused or council suggested this route
Timeline: 2-3 weeks for pre-app meeting + 8-13 weeks for decision
Cost: £200-500 pre-app fee (varies by borough)
When: Refused proposal was close to PD limits
Timeline: No planning permission needed (or 8 weeks for prior approval)
Cost: £0 (lawful development certificate free in most cases)
Honest assessment based on appeal complexity:
Resources: Design For Me's guide to DIY appeals provides templates and tips.
Refusal Reason: Excessive depth would harm neighbor amenity
Appeal Argument: 5m depth complies with SPD guidance, 45° test passed
Outcome: Inspector agreed council misapplied own policy. Appeal allowed.
Key Lesson: Know the local plan/SPD better than the planning officer
Refusal Reason: Roof terrace would create unacceptable overlooking
Appeal Argument: Proposed screening would prevent overlooking
Outcome: Inspector found screening insufficient, upheld refusal
Key Lesson: Genuine amenity concerns hard to overcome with mitigation alone
Refusal Reason: Committee refused against officer recommendation
Appeal Argument: Officer report correctly identified compliance with policy
Outcome: Inspector sided with professional planning assessment
Key Lesson: Political refusals often overturned on appeal
Count from the date on the decision notice, not when you received it. No extensions granted.
"We really need this extension" or "neighbor is unreasonable" don't work. Stick to planning policy and evidence.
Appeals assess what was refused, not revised schemes. Resubmit instead if you want to change design.
Address every single reason for refusal directly. Inspectors dismiss appeals that don't engage with the issues.
Householder appeal statements should be under 1,000 words. Be concise and focused.
12 weeks from the date on the decision notice for householder applications (home extensions). This deadline is strict - miss it and you cannot appeal. The 12 weeks starts from the decision date, not when you receive the letter.
Yes, but success rates are lower for conservation area refusals (typically around 20-25%). Inspectors give councils more discretion on design and heritage matters. Appeals work better when refusal is based on misapplied policy rather than subjective design assessment. Consider revising the design to be more sympathetic to the conservation area instead.
The inspector's decision is final. You cannot appeal again on the same design. Your options are: (1) submit a new application with revised design addressing refusal reasons, (2) consider a smaller permitted development extension, or (3) judicial review on legal grounds only (expensive and rarely successful - only if inspector made legal error).
Not unless you behave unreasonably during the appeal process. According to GOV.UK costs guidance, unreasonable behavior includes missing deadlines, submitting false information, or not turning up to hearings. Simply losing your appeal does not trigger costs awards.
Written representations are faster (10 weeks vs 16 weeks) and cheaper (can DIY). Choose hearing if: (1) technical issues need clarification through Q&A, (2) you have strong evidence that needs presenting in person, (3) success rate matters more than speed/cost (59% vs 29%). Most householder extensions use written representations successfully.
You can submit additional evidence to support your original design (photos, technical studies, policy references). However, you cannot submit revised drawings changing the design - the appeal must assess what was refused. If you want to change the design, withdraw the appeal and submit a new planning application instead.
Appeal if: Council misapplied policy, comparable approvals exist nearby, officer recommended approval but committee refused, or you have strong evidence contradicting refusal reasons.
Don't appeal if: Genuine design/amenity issues, conservation area subjective concerns, or you can easily fix the problems and resubmit.
Timeline: 10 weeks for householder written representations, 16 weeks for hearing. Must lodge within 12 weeks of refusal.
Cost: £0 to DIY (29% success rate), £1,500-3,000 for consultant written (29% success rate), £2,500-5,000+ for hearing representation (59% success rate).
Overall: With 34% householder appeal success rate, appeals are worth considering if you have a strong case. But be realistic - if the refusal reasons are valid, redesigning and resubmitting is often faster and more cost-effective than appealing.
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