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The Amalgamation of Two or More Properties into One may Require Planning Permission

The High Court recently held[1] that a local authority was entitled to rely upon their own analysis of the effect of housing amalgamations to the overall housing supply in the area when deciding whether the conversion would be material change of use requiring planning permission. With local authorities under increasing pressure to deliver more homes, this decision would mean property developers should seek planning permission prior to acquiring properties.

Facts of the case

The Royal Borough of Kensington and Chelsea (RBKC) refused to grant a Certificate of Lawfulness (“CLOPUD”) for a proposal to amalgamate two dwellings into a single maisonette on the basis that the loss of a residential unit ran contrary to their targets for the delivery of an increased housing supply. An increase in amalgamations across its administrative area was having a significant impact on its housing provision. However, such a position was not supported by their local planning policy and the developer appealed.

The Inspector found against RBKC. The local plan provided that the loss of 5 or more housing units would be resisted, but this had not been updated to reflect the stance now being adopted. In the absence of support in its local plan, the Inspector overturned the decision by RBKC.The Council sought a Judicial Review of this decision.


The Court ruled that the Inspector had made an error in law by referring to the support of planning policy as the determining factor in the case. The application for a CLOPUD was duly referred back to the Secretary of State for a further decision.

RBKC could rely on their analysis of the effect of conversions on housing supply as a factor to support their view that the proposal should be treated as a material change of use requiring planning permission. The Inspector has to consider the significance of that factor. The Inspector was not entitled to decide that question solely by ruling that the factor relied upon was unsupported by planning policy.


This case is of significance for developers because it demonstrates that Local Planning Authorities have a degree of flexibility to address changing priorities without necessarily having to update its planning policy. In this instance, RBKC’s stance was supported to an extent, but its position had changed and its planning policy had not yet caught up.

Nevertheless, the Court supported the view that the changing priorities and development landscape within the area with its impact on housing stock could be relevant considerations. It is clear that the facts of each case will need to be considered on each occasion that development such as this is contemplated. For example, developers hoping to amalgamate units in London should be mindful that collectively the Councils are under pressure to build 50,000 new homes every year meaning they should seek planning permission before acquiring property for amalgamation.

[1] R (Royal Borough of Kensington and Chelsea) v Secretary of State for Communities and Local Government [2016] EWHC 1785 (Admin)

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