London Borough update on their their Policy stance on Amalgamations

The prospect of Creating a larger dwelling without the need for planning permission is an attractive proposition, where it can adding both space and value to the property

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Achieving this by merging two adjacent properties is a popular option in some parts of London where, contrary to markets elsewhere in the country, one larger property can be worth more than the sum of its parts.

Bell Cornwell News
Author Alex Yearsley
Principal Planner
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As defined under Section 55 of the Town and Country Planning Act 1990, the amalgamation of two or more dwellings into one is not normally considered ‘development’.  This means that planning permission may not be required, including internal works on non-Listed Buildings.

However, we highlight that London boroughs are now taking a different approach since the adoption of the London Plan in March 2021 as Policy H8 part (a) seeks to restrict the loss of existing housing. which you may need to .  A few key examples are considered in this article:

Kensington and Chelsea

The Council’s long-standing view is that the amalgamation of units is a material change of use and therefore does require planning permission.

The Council has defined this in their Local Plan which was adopted in September 2019 and sets out their approach to amalgamating units. The policy was written to protect the Borough’s existing housing stock, prevent a reduction in the overall number of homes and to ensure the loss of units didn’t hinder their ability to meet future housing need.

The Council identify a strong market demand in the borough for very large homes, .

RBKC Policy CH1 states that the Council would only allow for amalgamation of units if the net loss of units is one and that the new dwelling would be less than 170 sq.m. Planning permission is still needed on any such application to determine its compliance with the policy.

However, RBKC’s new Local Plan is just around the corner, and we expect adoption to occur in late 2023.  Once adopted, RBKC will restrict all proposals that seek to amalgamate existing self-contained (Class C3) homes.


The London Borough of Camden take a slightly different view and have a higher threshold for what is considered to be a material change of use.

The Local Plan was adopted in 2017 and Policy H3 seeks to protect existing housing by resisting development that would involve the net loss of two or more homes, meaning that they consider there is no material change of use where there would be the net loss of one unit.

The policy provides exceptions, so that applications could be supported where the proposal would provide ‘large homes’ in areas where there is a low concentration of such housing and where the existing units provide sub-standard accommodation.

There are many examples in Camden where two units have been amalgamated to create one home without planning permission, often where a previously large single dwelling was subdivided in the past, and the original form is restored through ‘de-conversion’.

We recommended that a is obtained before undertaking the physical work to amalgamate units in these circumstances to secure a formal confirmation from the Council that planning permission is not required.


Westminster, whose City Plan was adopted in April 2021, take a different approach again in Policy 8. The policy drivers are to encourage the provision of affordable housing, as well as protecting existing housing stock and restricting the development of ‘super-sized’ homes (defined as more than 200 sq.m).

The policy also confirms that the net loss of one smaller unit to provide for a family-sized unit, particularly in de-conversion situations, or where existing units are of sub-standard accommodation, can be supported.

This policy wording is being strictly applied and applications are often refused even in de-conversion situations where the new unit would be more than 200 sq.m. In light of this policy,


Following the recent adoption of their new Local Plan in July 2023, Wandsworth have also increased the limitations on the amalgamation of existing residential units in the Borough with the relevant policy (LP25) following in a similar to that of Westminster and RBKC’s approach whereby a floorspace limitation is imposed.

The policy states that the net loss of self-contained residential dwellings will only be acceptable where the proposal involves combining no more than two non-family-sized dwellings in order to create a family-sized dwelling.

Additionally, the total floorspace of the new dwelling created must be less than or equal to 130sqm.  This will clearly impact numerous amalgamation projects going forward.


Perhaps London’s most stringent approach to amalgamation; Lambeth adopted their Local Plan in November 2021.

Local Plan Policy H3 seeks to safeguard existing residential units and is driven by the corresponding which states that the loss of existing housing should be replaced by new housing at existing or higher densities with at least the equivalent level of overall floorspace.

The policy does facilitate amalgamations but only in the prescribed circumstances whereby the proposal is for specialist to meet an identified local need, such as sheltered housing or assisted living facilities.

There is no floor area stipulated in the policy, which indicates that all amalgamation proposals resulting in the loss of units would be unacceptable in principle (unless meeting the above specific exception) with recent decisions providing corroboration for this.

We recommend this policy is carefully considered prior to making any investment decisions in residential property where the ultimate intention is to amalgamate dwellings, as the options are severely limited.


Islington’s stance in respect of the amalgamation of residential properties is relatively straightforward.  Islington’s Strategic and Development Management Policies was adopted in September 2023 and Policy H2 deals with the amalgamation of self-contained residential units.

The policy states that amalgamations shall be accepted provided the housing is replaced by at least the equivalent floorspace and would not result in the net loss of more than one unit.

What is unique about Islington’s policy is that it specially states in the text that the amalgamation of two or more units into a single dwelling requires planning permission.


















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Generally speaking, planning policy across London Boroughs is focused on protecting existing housing stock, maximising affordable housing and restricting ‘super-sized’ homes.

This is achieved by individual Boroughs defining what is important to their strategy and making clear what they consider to be material. The nuance of each policy needs to be taken into account at an early stage, which can have implications for the planning strategy for development proposals.

As planning experts, we translate these complex policies so you can identify solutions that satisfy local requirements. Our insight and experience with each council’s approach allows us to develop creative strategies aligned with their priorities from the start.

Get in touch with us now .



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