This guide explains planning permission rules affecting annexe developments in Westminster.
Most householder development follows national permitted development rules unless local restrictions apply.
Development must comply with national permitted development height limits.
Extensions must comply with national permitted development depth limits.
All planning applications in Westminster are determined in accordance with adopted policies in the 'Development Plan'. In Westminster, the Development Plan consists of three parts – the Westminster City Plan (produced by the council), Neighbourhood Plans (produced by designated Neighbourhood Forums with support from the council), and the London Plan (which is produced by the Mayor of London and provides strategic policies for all of Greater London). All such documents can be accessed below.
Roof alterations must comply with national permitted development rules.
Policies in the NPPF can be used directly to determine planning applications in Westminster as a material consideration, however, they are not part of Westminster's Development Plan.
Additional planning restrictions may apply in conservation areas.
Listed building consent is required for works affecting listed buildings.
Last verified 2026-01
UK permitted development legislation allows many annexe projects without planning permission provided certain limits are followed.
However local planning authorities such as those covering Westminster may impose additional planning controls through conservation area policies or Article 4 directions.
Many annexe projects in Westminster may fall under permitted development rights if they remain within national planning limits.
Development must comply with national permitted development height limits.
All planning applications in Westminster are determined in accordance with adopted policies in the 'Development Plan'. In Westminster, the Development Plan consists of three parts – the Westminster City Plan (produced by the council), Neighbourhood Plans (produced by designated Neighbourhood Forums with support from the council), and the London Plan (which is produced by the Mayor of London and provides strategic policies for all of Greater London). All such documents can be accessed below.
Yes. Additional planning restrictions may apply in conservation areas or where Article 4 directions remove permitted development rights.
Planning applications for annexe projects in Westminster are handled by the local planning authority covering Westminster, Greater London.
For official planning advice consult the council planning portal for your area or visit the UK Planning Portal.
This guide summarises planning rules affecting annexe developments in Westminster.
Planning regulations may change and additional local planning policies may apply. Always confirm planning requirements with your local planning authority before starting development.
Last updated March 2026