That proposed new basement: Does it require planning permission?

The owner of a terrace dwelling house in an urban setting wants to build or construct or excavate or create (whatever is the correct word) a basement. These days it is often cheaper and more convenient to extend the house rather than sell and move elsewhere, and anyway the owner likes their current location. Do they need planning permission or is the proposal covered by permitted development? What is the relevant planning law they have to observe?

The objections from neighbours and others come as no surprise:

• The stability of the structure of the neighbouring houses will be undermined;

• There will be an effect on the flood risk and drainage;

• The construction will be lengthy and noisy, with lorries removing spoil, traffic, and parking problems;

• The long-term impact, including more people, vehicles, and parking problems, will change the character and amenity of the area; and

• An undesirable precedent will be set.

The enlargement, improvement, or other alteration of a dwelling house requires planning permission, unless it be a minor matter in terms of size and volume and position, in which case it enjoys permitted development rights and in effect deemed permission (section 57 of the Town and Country Planning Act 1990 and the Town and Country Planning (General Permitted Development) (England) Order 2015). Section 55(1) of the Act distinguishes between building operations, which may be covered by permitted development, and engineering operations, which are not covered by permitted development.

So the issue arises: is the construction of a basement development (i.e. an enlargement of a dwelling house) or engineering (i.e. a separate substantial activity)? Is the work involved the sort of work normally done by a builder, including perhaps a highly skilled builder, or the sort of work normally done by an engineering company, requiring the expertise of a civil structural engineer, substantial excavation, heavy machinery, iron bars, structural support, and all such paraphernalia?

Faced with this problem in R (Eatherley) v Camden LBC [2016] EWHC 3108 (Admin), the judge held that the issue is one of fact and degree, an objective issue, to be determined on the evidence and in a rational and reasonable manner by the decision maker. Then the ultimate decision becomes a planning judgment soundly based. The creation of basements in urban areas is proving to be rather controversial and public authorities and private interests are concerned about the impact on neighbours and the neighbourhood. There are ways of depriving the owner of permitted rights:

• The building is listed;
• The building is in a conservation area; or
• An article 4 direction covers the area.

Alec Samuels is a barrister and former reader at Southampton University