Planning permission for a basement
London’s second most-applied-for project. Why most basements need a full application, and what the approval numbers really say.
Why basements rarely have a shortcut
Several inner-London boroughs have removed any permitted development route for basement excavation with Article 4 directions — Kensington and Chelsea's covers "Basements" explicitly. Lightwells visible from the street, engineering works and structural alterations push schemes to a full application in most cases, and several boroughs also have basement-specific Local Plan policies limiting depth and extent.
What the application must cover
Expect to submit a structural method statement, a construction management plan, and — in conservation areas — a heritage statement covering anything visible from the street. Where protected trees stand near the excavation, an arboricultural impact assessment joins the list.
In London, strategic drainage policy also applies: how the site handles surface water after excavation is a standard officer question.
“surface water run-off is managed as close to its source as possible. There should also be a preference for green over grey features”London Plan Policy SI 13 · full text in the library → · official source →
Reading the numbers
High approval rates for basements in established basement territory reflect well-prepared schemes, not a low bar — every application is tested in full, and preparation is what separates the 82% from the rest.
See it in a complete report
In our Notting Hill example, 116 of 142 decided basement applications within 1 km were approved — 82%.
General guidance ends here. Your property is specific.
The free check reads the designations on your exact property in seconds. The full report applies the policies above — and your council’s own Local Plan — to your project, with every quote verified against its source.