Basement development is not authorised under Class A permitted development rights in circumstances where the engineering operations that are required before building the basement, such as excavation and structural support, amount to a “separate activity of substance”, according to a significant judgment by Cranston J in R (Eatherley) v Camden Council  EWHC 3108 (Admin), handed down on Friday 2 December 2016.
To the relief of those concerned about the unassessed planning impacts of subterranean development, the judgment is likely to cause many basement proposals to require an application for planning permission, and local planning authorities will have to ensure that their approach to such proposals is consistent with the decision.
The claimant, Mr Eatherley, successfully challenged the decision by Camden Council to grant a certificate of lawful development for a single-storey basement extension relying on the permitted development right to carry out “the enlargement, improvement or other alteration of a dwellinghouse” (Schedule 2, Part 1, Class A of the of the Town and Country Planning (General Permitted Development) (England) Order 2015) (“GPDO”).
Cranston J held that Camden Council had misdirected itself by stating that, so long as the engineering operations were “necessary” for the basement development to occur, they automatically fell within the scope of Class A. The judge found that approach to be inconsistent with the relevant case law, according to which an activity could, as a matter of fact and degree, be a “separate activity of substance” even if necessary for and integral to the development authorised under the GPDO.
This is the first time that the High Court has directly dealt with whether a residential basement extension, involving significant excavation works, is or can be within the Class A right. The judgment clarifies a controversial topic in planning law and provides much-needed guidance to authorities who have hitherto adopted divergent approaches.
The decision is likely to also have an impact on the permitted development regime more generally.
A copy of the judgment is available here.