Basement
conversions
in Regent's Park, NW1

Camden's appraisal says ground levels round the park terraces were raised partly to make the most of the service areas and basements beneath.

We separate two jobs at the start: refitting an existing lower ground floor, and any new excavation, which brings a different set of consents.

Source: Camden: Regent's Park Conservation Area Appraisal and Management Strategy (adopted 11 July 2011)

Camden resists basements and their lightwells where they would harm the conservation area.

New lightwells can upset the building's relationship with the street, take garden space and clutter the front with railings.

Rooflights in a front garden can spill light from rooms below ground.

Policy A5 limits a basement to one storey and no more than half of each garden, among other tests.

A Basement Impact Assessment must show damage to neighbours no higher than Burland Scale 1.

For a Camden address we commission the ground investigation before design, because the Impact Assessment decides what is possible.

Sources: Camden: Regent's Park Conservation Area Appraisal and Management Strategy (adopted 11 July 2011), Camden Local Plan 2017

Camden's appraisal records a basement under the open space in front of Cambridge Terrace, and says future schemes there must keep or reinstate the landscaping and avoid large mature trees.

Basements under gardens have already changed the setting of some buildings.

Camden resists the loss of gardens, soft landscaping and original boundary walls to basement work.

Where trees are on or next to the site, an arboricultural report goes with the application.

Our engineer and arboriculturist walk the garden together before any outline is fixed.

Source: Camden: Regent's Park Conservation Area Appraisal and Management Strategy (adopted 11 July 2011)

Camden generally requires a Construction Management Plan for basement work.

For basement extensions it must be satisfied the building and neighbours will stay stable during works.

Vehicles over 28 tons and cranes of any weight need a special licence from the Paving Commission.

Westminster's Code warns against placing skips or heavy plant over vaults without careful thought.

Spoil leaves in small loads on a covered vehicle, and the pavement vaults on the route are checked before the first lorry arrives.

Sources: Camden Local Plan 2017, Camden: Regent's Park Conservation Area Appraisal and Management Strategy (adopted 11 July 2011), Crown Estate Paving Commission: Standard Licence Terms and Conditions, Westminster City Council: Code of Construction Practice (May 2026)

Westminster's City Plan accepts basements reaching up to 1.8 metres under the highway, with at least 900mm between the road surface and the vault.

The Paving Commission bars vehicles from pavements, to protect the vaults below, without protection and written permission.

Existing vaults are measured and their crowns inspected from below before any change of use, and their drainage is cleared first.

Sources: Westminster City Plan 2019-2040 (2026, adopted January 2026), Crown Estate Paving Commission: Standard Licence Terms and Conditions

Camden's appraisal says a new unit formed by excavating a basement will not normally be accepted where it harms the conservation area.

Camden expects a demolition or construction management plan for basement works in a conservation area or next to a listed building.

If the aim is a separate lower-ground flat, we test that question with the council at pre-application stage before any engineering is paid for.

Sources: Camden: Regent's Park Conservation Area Appraisal and Management Strategy (adopted 11 July 2011), Camden Planning Guidance: Basements (January 2021)