Mayor should crack down on mega-basement developments

Outside a mega-basement development with concerned resident

Outside a mega-basement development with concerned residents

Subterranean development is a growing issue in some parts of London, where the super-rich are digging deeper and wider in an effort to cram swimming pools, cinemas, and gyms into often historic homes. These developments can cause flooding, sink holes and structural damage to neighbouring buildings and construction is often severely disruptive to the neighbourhood.  The worst-affected boroughs have policies to limit inappropriate basement development, but without the backing of a strong policy in the London Plan they will find it difficult to enforce and can see their decisions overturned by inspectors.

Most local authorities have planning policy on basement development but four of the boroughs where the problem is most acute; the London borough of Camden, Hammersmith & Fulham , City of Westminster and the Royal Borough of Kensington and Chelsea (RBKC) have or are developing special policies to tackle it.  In 2013 alone, there were 1,709 applications for these mega-basements in RBKC; 1,405 in the City of Westminster; 754 in Camden; and 616 in Hammersmith & Fulham.

A recent report on the planning application for one of the largest and most opulent basements in Holland Park included a cigar room, yoga studio, two-level gymnasium and a six car stacker system. This is unashamed decadence at its worst; the super-rich shouldn’t have free reign to afflict the ground beneath us because of lax planning law in London.  Restrictions on basement expansion must be tightened to avoid iceberg houses from becoming the norm and further putting upward pressure on land prices.

The damage to neighbouring houses is often devastating:

Peter Symonds, Chair of the Combined Residents’ Associations of South Hampstead highlighted the misery these developments bring about saying that ‘dozens of local residents who live close to basement excavations have seen their cellars and gardens flooded, experienced subsidence and serious destabilisation, and watched helplessly as elaborate Victorian ceilings and bay windows are bought crashing down’.

The Mayor’s draft Further Alterations to the London Plan does not include any basement development policy even though as the body which overseas strategic policy in London, the Mayor is best placed to tackle this problem.   This is why I proposed a motion at the last meeting of the London Assembly on the 5th of March.   The alterations currently being consulted on provide an opportunity to add a policy preventing inappropriate basement development.  Some of what the motion said is as follows:

“This Assembly notes that inappropriate basement development is an increasing problem within London………………. Despite the rising concern, the draft Further Alterations to the London Plan (FALP) does not include a specific policy on subterranean development. ……………………………………London must adopt stronger policies to help boroughs prevent unnecessary basement development, such as prohibiting extensions under listed buildings and limiting the size and depth of new and redeveloped basements. This Assembly therefore calls on the Mayor of London to revise the FALP to include a specific policy against inappropriate basement development”

Karen Buck MP’s Private members Bill, the Permitted Development (Basements) Bill 2013-2014 provides some guidance on the meaning of inappropriate basement development. Her Westminster North constituency has one of the highest concentrations of planning applications for these subterranean extensions.   The bill defines these as developments which include listed buildings, a depth of more than one storey and developments that cover more than 50 per cent of the garden area so this provides us with a good yard stick with which to measure.

The motion received unanimous cross-party support.  Despite the recent consideration of councils over planning, we need a revision of the FALP policy by the Mayor to include planning restrictions that can then be enforced. Councils have little command against the might of architectural companies, legal teams and the super-rich without such policy. If the Mayor introduces this policy into the London Plan then we can place tighter controls on these unnecessary and ostentatious underground developments.

The Mayor’s sister Rachel Johnson recently campaigned with other residents to block a planning application which would have seen a basement being built underneath a public road in Notting Hill.   So, if the Mayor does not listen to us then perhaps he should lend an ear a bit closer to home!

This piece has also been published in this week’s West End Extra.



The London Plan is the spatial planning strategy for London. The draft Further Alterations to the London Plan were published 15 January for consultation concluding on 10 April. The alterations can be found here:


2 thoughts on “Mayor should crack down on mega-basement developments

  1. Basements West London

    Nice post. Thanks for sharing. I think the government should take the necessary actions so that people do not put their neighbors life at risk for their own luxury lifestyle.

  2. oliver froment

    I am 100% for a cross party movment that prtoects neighbourhood against basement inflicted damages.

    Boris Johnson and the various London Bugough such as Camden should act to that effect swiftly.


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