Yesterday, in Lisle-Mainwaring and Force Foundations v Royal Borough Kensington and Chelsea  EWHC 2105 (Admin), Mrs Justice Lang dismissed an application to quash the recently adopted Core Strategy policy governing basement development in Kensington and Chelsea.
This policy takes the form of a list of criteria which include limits on (a) the lateral extent of a basement (no more than 50% of any garden) and (b) on the depth of a basement (no more than one storey).
There were two principal grounds to the challenge, the first of which claimed the Council, in adopting the policy, had failed to consider its effect on the take up of permitted development rights to construct basement extensions to dwelling houses. In support of the argument the Claimants pointed out that, while the Council did not intend to make an Article 4 direction before adopting the policy, this very consideration had, shortly after the policy was adopted, led it to make a Borough wide Article 4 direction removing those rights. If the Article 4 direction is confirmed, and assuming the Secretary of State does not intervene, it will take effect in 2016. While noting that the interpretation of the extent of PD rights is controversial and disputed, the Judge did not find it necessary to resolve any of those disputes [paragraph 45 and see the recent judgement of Patterson J in Royal Borough of Kensington and Chelsea v SSCLG (transcript awaited)]. The essence of her ruling on this first ground is at paragraph 73-74 of the Judgment.
The second ground of challenge claimed the Council's Sustainability Appraisal (incorporating its Strategic Environmental Assessment obligation) was flawed for a failure to assess a reasonable alternative to the Council's preferred policy. The legal requirement under the SEA Regulations was not in doubt, namely to "identify, describe and evaluate the likely significant effects on the environment of ... reasonable alternatives [to the preferred option] taking into account the objectives and geographical scope of the plan."
The true objectives of these two limiting criteria were at the forefront of argument and should be taken into account in their application [see for example paragraphs 90-93 and paragraph 109]. As argued by the Council, the objective of limiting the scale of basement development is to address the impact on residential amenity caused by the excavation of material during construction.
In dismissing the Claimants' arguments, the Judge has followed the ruling of the Court of Appeal in Ashdown Forest Development Ltd v Wealden DC  EWCA Civ 681 in holding that the question what is a reasonable alternative is a matter of evaluative judgment for the authority in question [see paragraph 123].
Her decision leaves the adopted Basements Policy, CL7 of the Core Strategy in place. Other related decisions remain to be taken, namely (1) whether to confirm the Article 4 direction recently made and consulted upon (unless of course the Secretary of State exercises his discretion to intervene); and (2) whether to adopt the second draft of a new Supplementary Planning Document which is intended to replace that adopted in 2009 and is currently the subject of consultation.
Harriet Townsend acted for the Claimants, led by Paul Brown QC of Landmark Chambers. They were instructed by Richard Max and Co.
The Judgment can be found here.