A HOMEOWNER has applied to build an underground swimming and gym leading to concerns from neighbouring residents.

Isabella Honeyman of The Dell in Woodford Green has already started building the extension which will eventually contain the pool and gym if permission is granted, but this has prompted neighbours to object to the plans.

Rochelle Posner who lives on the High Road and whose house backs onto the property said in an objection letter to the council: "We have grave concerns regarding both contamination issues, substantially natural differences in garden levels but especially the important trees under preservation orders directly adjacent to the site."

The two trees in question are both Turkey Oaks and are subject to a tree preservation order by the council, leading to an objection from the trees and landscaping department.

Mrs Posner added: "We are not against anyone improving and extending their homes in the traditional manner such as rear extensions which are disproportionate to the existing building, but this brand of home extension on an already heavily extended house in the shape of vast excavation work needs addressing urgently.

"Given the gardens are so close to each other we feel this would set a precedent for serious and inappropriate overdevelopment in relatively small but very mature gardens."

Her neighbours Roger and Madeleine Davis have also objected to the building work.

They said: "Waste from the filtration of the pool must be properly  controlled by direct access to the house main drainage and if this cannot be guaranteed there is a grave risk of seepage beyond their boundary causing contamination to neighbouring properties.

"There is an unknown effect that such large underground structure might cause to local drainage of underground rainwater, by either retaining or diverting it, causing possible flooding or subsidence problems in other properties in the area."

No date has yet been set for a decision to be made on the underground development.

The subject of underground developments in London is controversial as homeowners extend their homes beneath the surface because they can no longer build outwards.

A billionaire recently binned his plans to build a 50foot complex under his Chelsea home, which included a pool, cinema and staff quarters, because a provision for affordable housing had not been included in the design.