Which Planning Applications Get Refused Most Often?

Not all planning applications have the same refusal rate. Some project types sail through. Others get refused at rates that should make any homeowner pause.

We analysed refusal rates across every common application type using our dataset of 2,500,000+ real planning decisions from 226 UK councils. Here's the full picture — from the safest bets to the most refused proposals.

The Full Refusal Rate Ranking

This table ranks application types from most refused to least refused. The refusal rate is the inverse of the approval rates we've published elsewhere — but seeing it from the refusal side changes how you approach your project.

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The Most Refused Group: 1 in 5 Refused

Three application types stand out with refusal rates above 18%.

Flat conversions (24.7% refused). Nearly one in four flat conversion applications is turned down. Converting a house into flats changes its character fundamentally — more residents, more parking pressure, more bins, more wear on shared spaces. Planning officers scrutinise these heavily, particularly in areas where councils are trying to protect family housing stock.

HMOs (21.4% refused). Houses in multiple occupation face similar resistance. Many councils now have Article 4 directions requiring planning permission for HMO conversions, and refusal rates reflect a widespread political desire to limit HMO proliferation, especially in university towns and inner cities.

Change of use (19.8% refused). Changing a building's use class — from commercial to residential, for example — attracts scrutiny because it affects the character of the wider area. Loss of employment space, increased residential density, and impact on the street all feed into higher refusal rates.

New builds (18.7% refused). Building something entirely new faces more scrutiny than extending something existing. Every aspect is assessed from scratch — siting, massing, design, access, drainage, impact on neighbours. There's no existing permission to lean on.

The Middle Group: 10–15% Refused

Most extension types sit in this band. Dormers at 14.3%, loft conversions at 14.0%, basements at 13.7%, and side extensions at 10.2%.

The common thread? These projects all add visible bulk or height to a property. Dormers change the roofline. Side extensions close the gap between houses. Basements, perhaps surprisingly, face scrutiny over construction impact, structural concerns for neighbouring properties, and drainage effects.

If your project falls in this range, preparation matters. Knowing what your specific council approves and refuses for your type of extension can be the difference between joining the 85% who get approved and the 15% who don't.

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The Most Approved Group: Under 10% Refused

Rear extensions, wraparounds, and conservatories are the safest bets in planning. Rear extensions are refused just 9.4% of the time across 186,137 decisions — the largest sample in our dataset. Conservatories at 6.8% are practically a formality.

Why are these so safe? They share three characteristics: minimal impact on the street scene (they're at the back), strong local precedent (every street has them), and familiarity for planning officers (they process thousands every year). When an officer sees a well-designed rear extension, the default instinct is to approve unless there's a clear reason not to.

Your Council Changes Everything

These are national averages. Within any single project type, refusal rates can vary by 20+ percentage points between councils. A dormer that has a 5% refusal rate in one council might face a 25% refusal rate in another.

The councils that refuse most tend to be urban, densely populated, and under significant development pressure. London boroughs feature heavily at the stricter end. Rural councils and those in less pressured areas tend to be more accommodating across all project types.

This is why checking your specific council's data before you apply is so important. The national refusal rate for your project type sets the scene. Your council's rate tells you what you're actually facing.

How to Use This Data

If your project type is in the most approved group, you can approach planning with reasonable confidence — though still check your local area for any specific patterns.

If you're in the middle group, invest more time in understanding what your council approves. Look at comparable decisions nearby. Consider whether minor design adjustments could push you toward the approved column.

If you're in the most refused group — flat conversions, HMOs, change of use — you should treat planning as a genuine hurdle, not a formality. Pre-application advice from the council, a planning consultant, and a careful review of what's been approved and refused nearby are all worth the investment. The cost of a well-informed application is far less than the cost of a refusal.

The data doesn't determine your outcome. But it tells you the landscape you're operating in — and that's the starting point for every smart planning decision.