Controversial plans to expand a Highgate girl’s school and build a 300 seat underground theatre could divert subterranean waterflows and endanger the surrounding historic environment, residents have warned.

Controversial plans to expand a Highgate girl’s school and build a 300 seat underground theatre could divert subterranean waterflows and endanger the surrounding historic environment, residents have warned.

Channing School, in The Bank, Highgate, wants to build a new sports hall and plans to drill several metres underground to construct a performing arts centre, under large scale proposals to update its facilities.

The plans have sparked a flurry of protest from residents, however, who have raised concerns the redevelopment will harm the historic raised wall of The Bank and create an “ugly” eyesore in the conservation area.

They have also objected to a wall which will enclose the site and separate it from neighbouring gardens.

Nick Silver, whose Grade II * listed home backs onto the school, said: “An enormous amount of earth will have to be removed from the site. It will change the level of the underground waterflow which will be serious for residents.

“There is going to be congestion, noise and we are very concerned that they are going to be digging so deep into the ground.

“Frankly, the residents feel this is going to completely alter the nature of our properties, and the building is ugly.”

Other residents warned that the constant flow of lorries needed to ship earth away from the site pose a serious treat to the listed historic wall which runs alongside The Bank.

Adrian Mayer, 88, has lived in Highgate Hill for more than 50 years and sent his two daughters to Channing.

He said: “I live next door to Channing and I am all for them improving it, but there are problems.

“The Bank is a listed historic wall and it is not in a very god condition. If there are a lot of lorries going up and down it could damage it.

“It has already collapsed once or twice before.”

Channing School says the redevelopment is desperately needed to update its facilities and has been carefully designed not to harm the conservation area.

But Mr Silver, who has lived in his Highgate home for 12 years, vowed to fight the plans.

“I’m happy to chain myself to the railings or do whatever it takes to stop them. I’m just not going to take this lying down.”

Roy Hill, Channing’s bursur said: “Channing School undertook a thorough consultation programme with residents and local groups such as the Highgate Society as the proposals were being developed prior to the making of the planning application.

“The proposals were altered to take into account comments raised.

“It is important to emphasise that the proposed works are not linked to an expansion of the school.”

A meeting to discuss the proposals will be held at the school on Monday 10.