Westminster Council has “missed its chance” to take a stand against the development of mega-basements after controversial plans to excavate a double basement and create luxury homes in a quiet Marylebone mews have been given the go-ahead.

A panel of councillors has shocked residents and businesses by green-lighting the development of Oldbury Mews at a planning committee meeting on September 10, despite fierce opposition to the scheme, including a 500-strong petition handed to the council’s planning officers.

The old Bramah locksmith building in Oldbury Place will be demolished and replaced by three townhouses with double basements which will be used as gyms and cinemas.

Judy Sibley, who lives opposite the proposed development, said: “We think the council has missed a great opportunity: there was an opportunity for them to set the tone. Everyone is so appalled. It will be two years of disruption in the mews. It will be basically 10 trucks a day.”

The resident said the council was tied in because it hasn’t got a “basement policy”. She added: “No one knows the effect of digging down six metres for a double basement.”

Yuval Zommer, who is fighting a similar double basement scheme in Botts Mews, Westbourne Green, also expressed his incredulity at the council’s decision.

He said: “With guidelines being prepared to curb the rash of basement applications, this was an ideal opportunity for the council to take a stand.

“To my amazement, the planning committee just rubber stamped this controversial planning application. It is bitterly disappointing.” Opposition to the development includes objections from St Marylebone School for Girls, the Maldives embassy and Princess Grace Hospital, both in Nottingam Place.

Iceni Projects, the planning consultancy, was unavailable for comment.

Cllr Robert Davis, the council’s deputy leader, said: “We are continuing to do everything we can to limit their spread and ensure where basement extensions do take place, they are sensitive to the local area. I believe our policy, which you will shortly see for consultation, reflects this position.

“Whilst it may not be the silver-bullet many residents hope for, the policy will be as robust as we can be on this issue, within the existing law.”