The London Plan and What It Means for Homeowners Extending Their Properties

Introduction

The London Plan is the Mayor of London's statutory spatial development strategy for Greater London. It sets out a planning framework for the whole of London, which all London boroughs must follow in their own Local Plans and planning decisions. While the London Plan is primarily associated with strategic planning (major developments, housing targets, transport infrastructure), it also contains policies that are material to householder planning applications. Understanding the relevant London Plan policies helps homeowners and their architects prepare stronger planning applications.

The London Plan 2021

The current London Plan was published in 2021 (adopted March 2021) and is the overarching strategic planning document for Greater London. The Mayor's policies take precedence over local policies where there is a conflict, though boroughs can apply more detailed and locally specific policies within the London Plan framework.

Design Quality: Policy D3 and D4

London Plan Policy D3 (Optimising site capacity through the design-led approach) and D4 (Delivering good design) are relevant to all development, including householder applications in certain circumstances. The policies require that development:

• Demonstrates high-quality design that responds to the character of the local area
• Creates buildings and spaces that are functional, accessible and inclusive
• Respects and enhances the local natural and historic environment
• Is designed for long-term durability and adaptability

For householder applications, these policies are typically addressed through the local borough's own design policies, but where applications are called in by the Mayor (a rare occurrence for householder applications) the London Plan design policies would be directly applied.

Heritage: Policy HC1

London Plan Policy HC1 (Heritage conservation and growth) requires that development affecting heritage assets — including listed buildings, conservation areas, scheduled monuments and registered parks — protects and enhances their significance. The policy aligns with national NPPF heritage policies and requires that:

• Development that would cause substantial harm to a designated heritage asset is refused unless there is an exceptional case
• Development causing less-than-substantial harm must be justified by demonstrating that the public benefits outweigh the harm
• Development should seek opportunities to better reveal the significance of heritage assets where possible

Sustainable Design: Policy SI 2 and SI 3

The London Plan's sustainability policies are increasingly relevant to householder applications. Policy SI 2 (Minimising greenhouse gas emissions) and SI 3 (Energy infrastructure) encourage development to minimise carbon emissions and incorporate renewable energy where feasible. While these policies primarily target major developments, some London boroughs have adopted locally specific sustainability requirements for householder extensions that reference London Plan sustainability objectives.

Accessibility and Inclusive Design: Policy D5

London Plan Policy D5 (Accessible and inclusive design) requires that development is designed to be accessible and inclusive for all users. For householder applications, this typically means ensuring that any new accommodation (particularly ground floor extensions accessible from the street) meets accessibility requirements under Part M of the Building Regulations. Some London boroughs have more detailed local policies on accessible and adaptable homes that supplement the London Plan requirements.

Residential Amenity: Policy D6

London Plan Policy D6 (Optimising housing density) and associated policies on residential quality set minimum space standards for new residential accommodation. While these primarily affect new housing development rather than extensions to existing homes, they provide context for local borough requirements on minimum room sizes and floor areas.

Play Space and Green Infrastructure: Policy G5

Policy G5 (Urban greening) and G7 (Trees and woodlands) require that development protects and, where possible, enhances the urban green infrastructure. For householder extensions, this has implications for how garden space is treated — particularly where extensions significantly reduce the amount of garden, or where trees protected by TPOs or conservation area designation might be affected.

How the London Plan Affects Your Planning Application

For most straightforward householder applications, the London Plan policies are applied through the local borough's own Local Plan and SPDs, which must be consistent with the London Plan. The borough planner will assess your application against both local and London Plan policies.

The London Plan becomes directly relevant when:

• The proposal is in a designated area (conservation area, World Heritage Site setting)
• The proposal involves a large-scale residential extension or change of use
• The application is called in by the GLA for representations (rare for householder applications)

Conclusion

The London Plan establishes the strategic planning framework within which all London borough planning decisions must be made. For homeowners, its most direct relevance is through the heritage, design quality and sustainability policies that flow through into borough Local Plans and SPDs. Working with an architect who understands the London Plan framework and how it interacts with the specific policies of your borough will ensure that planning applications are well-prepared and credible across all relevant policy dimensions.