Children from a Hampstead school stormed Camden Town Hall last night and managed to persuade councillors to reject a planning application.

Armed with placards and banners the pupils, from St Christopher’s School, in Lyndhurst Gardens, protested on the steps of the Town Hall, in Kings Cross, chanting “education not excavation’ and ‘let us learn’ before the meeting to stop a luxury house with a double depth basement being built next to their school.

After the demonstration the four to 11-year-olds took their place in the public gallery and waited patiently before the item was presented before the chamber.

The youngsters had complained that the dust and noise from building work would have stopped them being able to use their science block, which is little more than a metre away from the proposed site.

The developer, Lyndhurst Gardens LLP, wanted to demolish the 1970s two-bedroom bungalow to make way for a three-bedroom house with a swimming pool, gym and sunken courtyard.

But the school was worried about the disruption it might cause to its pupils.

The nearby Marie Curie Hospice was also concerned about the effect the work would have on patients.

Representing the school was mother and QC Fiona Parkin, of Wedderburn Road, Hampstead, whose daughter is a St Christopher’s pupil.

She said: “Any replacement building should enhance the conservation area to a greater extent than the existing building.

“That is the test that has to be applied.”

As planning permission was refused, cheers rang out across the council chamber from the delighted school girls, their parents and teachers.

Proud parent Jackie Orlick said: “We came here tonight because we felt there had been no dialogue from the developer with the school. “This is the only way the girls could make their voices heard.

“We are always being told about young people being disengaged from the political process.

“So it was great that they came here tonight and engaged with what is going on in their community and have their say.”

Cllr Chris Knight (Conservative), ward councillor for Hampstead Town, said: “I’m absolutely delighted for the children.

“It has given them an insight into local politics. I hope it will encourage them in the future and will leave an impression with them to remember for their rest of their lives. Who knows? Maybe there were some future politicians and activists here tonight.”

The application was refused on the grounds that it significantly failed to enhance the conservation area and would impact on gardening area.

The applicant, Hampstead company Vabel, said: “We are glad that councillors accepted the independent professional advice that our proposals for the design and construction of this low key highly sustainable family home complied with council policy and would not harm the local environment. We are grateful to those residents who expressed support for the plans.

“We have worked hard to ensure our proposals respect and protect the neighbouring school environment, as well as confining the noisiest works to school holidays and planting additional trees along the site boundaries.

“Naturally we are disappointed that the application and the opportunity to enhance the conservation area was not approved and are now considering our position.”