Not all planning applications are treated equally. Larger developments are classified as "major applications" and go through a more involved process than a typical extension or single new home.
What counts as "major"
Under national planning policy, an application is classified as major development if it involves:
- 10 or more residential units — or, if the exact number isn't specified, a site area of 0.5 hectares or more
- For non-residential development: 1,000 sqm or more of new floorspace, or a site area of 1 hectare or more
Anything below these thresholds is classified as a minor application (or, for household projects like extensions, a householder application) and follows the standard process.
Why major applications take longer
Major applications get a 13-week statutory determination period, compared to 8 weeks for most other applications — reflecting the genuinely greater complexity involved: more extensive consultation, more technical assessments (transport, drainage, ecology, and so on), and often negotiation over planning obligations. It's common, and not necessarily a bad sign, for this period to be extended further by agreement between the applicant and the council.
Outline permission is common for large sites
Many large-site applications come forward as outline applications first — establishing whether the principle of development is acceptable, with detailed design matters ("reserved matters" — appearance, landscaping, layout, scale, and access) submitted later in a separate, follow-up application. This lets developers secure certainty on the fundamental question before investing heavily in detailed design.
Planning obligations and contributions
Large developments often come with planning obligations — commitments (sometimes financial, sometimes in the form of built infrastructure) tied to the permission, covering things like affordable housing, school places, or local road improvements. These are genuinely part of how the planning system tries to make sure a large development contributes to the infrastructure it creates demand for, rather than just adding pressure to existing local services.
Committee decisions are more likely
While plenty of applications — major or otherwise — are decided by planning officers under delegated powers, major and contentious applications are considerably more likely to go before a planning committee of elected councillors for a public vote. If you want to have your say on a large development, checking whether it will go to committee (and when) is worth doing directly with the council.