The Definitive Guide to UK Planning Permission

Navigating the UK's planning system is often cited as the single highest-friction barrier to property development. In 2023, local planning authorities in England received 354,000 applications, with an average approval rate of 86%, but decision timelines frequently stretched well beyond the statutory 8-week target.

1. Understanding Permitted Development Rights (PDR)

Before applying for full planning permission, determine if your project falls under Permitted Development Rights. The General Permitted Development Order (GPDO) allows for specific types of work without a formal application, subject to strict dimensional and volumetric limits.

Development Type	Volume/Area Limit	Key Constraint
Single-storey rear extension	Up to 4m (detached) / 3m (attached)	Must not exceed 4m in height
Loft conversion	Up to 50m³ (detached) / 40m³ (terraced)	No higher than the highest part of the existing roof
Outbuildings	Max 50% of total land around original house	Max height 2.5m if within 2m of boundary

2. The Full Planning Application Process

If your project exceeds PDR limits or is in a designated area (Conservation Area, AONB, National Park), a full application is required.

Statutory Timeline: Local authorities have 8 weeks to determine a minor application (e.g., householder extensions) and 13 weeks for major developments. However, chronic under-resourcing means these targets are often missed.

Common Mistakes That Lead to Refusal

• Overlooking the Local Plan: Every local authority has a Local Plan. Applications contrary to this plan are almost universally rejected.
• Ignoring overlooking/loss of privacy: If your extension severely impacts a neighbour's right to light or privacy, it will be refused under 'unacceptable impact on amenity'.
• Inadequate drawings: Submitting sketches rather than scaled architectural drawings (typically 1:50 or 1:100) will result in immediate invalidation.

3. Interactive Tool: PDR Viability Checker

Use this tool to run a quick baseline check on whether your rear extension might qualify for Permitted Development.

4. Frequently Asked Questions