The 'basement extension' of the super-rich is a trend more commonly seen in posh parts of London than Birmingham.

But with space at a premium around some Brummies' luxury homes, well-heeled homeowners are looking to increase the size of their property. And they're looking down.

Furious neighbours insist homeowners should need their permission before creating the disruptive extensions.

The call came after the owner of a semi-detached home in Chantry Road, Moseley, was given the go head to dig out a basement extension for an 11 metre swimming pool.

A house in Chantry Road, Moseley, has been granted permission to build a basement swimming pool.
A house in Chantry Road, Moseley, has been granted permission to build a basement swimming pool.

Basement extensions have been very popular among the super-wealthy of central London where space is tight and property prices high - often they provide gyms or pools or underground garage space. But there have so far been very few in Birmingham.

Now council planners are calling for a policy to be drawn up - as there were required to approve the scheme despite complaints from the owners of the semi-detached house next door.

Planning committee member Barry Henley (Lab, Brandwood) said: “We don’t have a policy for this. It is the first one I can remember where someone is going to dig a big hole under a house.”

An underground pool

He said that the construction work will cause a huge amount of disturbance to the neighbour’s home and possibly some structural work. And pointed out that in some London boroughs there are now strict controls in place.

“Where a terraced or semi-detached house is involved I think the explicit consent of neighbours should be needed.”

His colleague Cllr Bob Beauchamp (Cons, Erdington) added: “I can see this open up a floodgates”.

Cllr Keith Linnecor (Lab, Oscott) asked for geological surveys to ensure there are no subsidence problems.

But council planning officers said that the safety and structural integrity of works was monitored by building regulations, not the planning process.

Chief planning officer Richard Goulborn said: “There have been a small number of basement extensions in Birmingham most of which do not require planning permission.

“They are a lot less likely here than in London because of the huge gulf in house prices.”

Only extensions with alter the external appearance of the property, such as a light well or outside steps or a ramp down or require planning permission. In this case the basement pool was part of a wider extension to the property.

Committee members were split over the plan, with four in favour, four against and four abstaining due to the lack of clear policy. The plans were approved on the casting vote of the chairman Mike Sharpe.