Permitted Development Rights provide an exception to the general rule that planning permission is required for any Development (as defined in the Town and Country Planning Act 1990 ("TCPA") on land.
These rights are however subject to a number of limitations and the recent case of Royal Borough of Kensington and Chelsea v Secretary of State for Communities and Local Government  EWHC 2458 (Admin) was concerned with the interpretation of these limitations for basement extensions beneath residential property.
Class A of Schedule 2 of The Town and Country Planning (General Permitted Development) Order 1995 permits development for "the enlargement, improvement or other alteration of a dwellinghouse." There are however a number of limitations contained within A1. Whilst these have been amended by the 2008 Order and have now been replaced by the 2015 Order, the wording as set out in A1 is not materially different.
In the 2008 Order, development is not permitted if:
"(f) the enlarged part of the dwellinghouse would have more than one storey and -
(i) extend beyond the rear wall of the original dwellinghouse by more than 3 meters or
(ii) be within 7 metres of any boundary of the curtilage of the dwellinghouse opposite the rear wall of the dwellinghouse;"
The RBKC Case
The background to the RBKC case is that RBKC refused two applications for a certificate of lawfulness for proposed use or development ("CLUPOD"). The applications were both for the addition of a single storey basement underneath residential properties which were 2 and 3 storeys respectively. RBKC refused to grant CLUPOD's relying on the limitation under (f) above.
The key question put before the court was whether RBKC's interpretation of "more than one storey" was correct. The court had to ask what the draftsman's intentions were and concluded that the draftsman had chosen his wording carefully to state "the enlarged part of the dwellinghouse" and not "the original dwellinghouse" - the significance is that the creation of a basement which would, by its very construction, create an additional storey to an existing dwellinghouse was not what was meant to be captured by the limitation. The question to be applied was whether the "enlarged part" of the dwellinghouse has more than one storey. In this case it was the construction of a single storey basement. What will be captured by the limitations in (f) is therefore a two storey or more basement proposal.
Why is this important?
As property prices escalate - particularly in London - more people are considering extending their properties underground so as to increase floor space and create a more comfortable living environment. This recent trend has resulted in an increase in basement excavations and extensions and some of these basement extensions are extravagant with underground swimming pools being built as well as spas, gyms and home cinemas.
As many basement extensions can be carried out without obtaining formal planning permission (and this case further supports this) they are not subject to the usual controls that the planning system can offer and therefore it is difficult for local authorities to determine or control the number of basement extensions being carried out in a local area.
Steps Councils can take
So what powers do councils have?
Under Article 4 of the GPDO, a local authority is able to make a direction so as to remove these permitted development rights. If Permitted Development Rights are removed under Article 4, the outcome is not to prevent basement development altogether but instead those wishing to construct a basement extension will be required to make a full planning application. However, this process is not without consequence as the local authority can be required to pay compensation if within 12 months of the Direction first being suggested it refuses planning permission for development which would otherwise have been permitted development.