The community has rallied against the proposed demolition of a historic mansion on the edge of Hampstead Heath that may have inspired the Rupert the Bear illustrations.

A fresh bid to demolish Athlone House in Highgate and replace it with an extravagant eight-bedroom family home, including a basement swimming pool, ballroom and roof terrace, was made to Camden Council two weeks ago.

Residents are gearing up once again to fight the proposals as part of their 13-year battle to save the 1870 mansion, which served as an intelligence base for the RAF and as a hospital before it was first sold to developers in 2000.

Athlone House Working Group member Catherine Budgett-Meakin, 67, of Bisham Gardens, Highgate, said: “I am utterly opposed for the same reason as the last application to demolish it. I think it is absolutely appalling that the developers think they can wear us down. I really hoped it would be turned into something for the north London community, whether that was a hotel or something else, if it is not going to be refurbished.”

An anonymous objector to the latest proposals said they believed that the building and its “castle-like turrets” inspired one of the illustrators of the Rupert the Bear books.

They wrote in an official response to the planning application: “I have been in Highgate for over 30 years and Athlone House is an integral part of the skyline.”

Athlone House’s owner, thought to be a foreign billionaire, bought the property in 2005 under the name Athlone House Limited. The owner sought to demolish it in 2009 but the plans were rejected by both Camden Council and the Planning Inspectorate on appeal.

Last year, Cllr Valerie Leach, cabinet member for planning, said it would difficult for the council to reject future proposals to demolish Athlone House because the planning inspector had ruled that the “damaged” mansion could ­potentially be replaced with a more attractive building.

Campaigners are fighting to have the house restored to its former glory, saying that owners have “ignored” a section 106 agreement made eight years ago which ­required them to refurbish it. Highgate Society environment committee member Michael Hammerson said: “The community is outraged by the developers ignoring the section 106 agreement. Last time, we had 550 letters of objection, which shows how strong the feeling is.”

An Athlone House spokesman said: “It is unrealistic to expect the new owner to implement the existing planning consent given the very poor condition of the building and the need to provide a very high quality living environment to meet today’s standards.

“The planning inspector ­accepted this reality and concluded that a new house would be acceptable subject to a high standard of design, which we believe Robert Adam has produced.”

Cllr Phil Jones, cabinet Member for transport, sustainability and planning at Camden Council, said: “This is a really important site and the council has long fought to preserve Athlone House.

“It is therefore extremely frustrating that a planning inspector has already concluded that demolition could be acceptable in some circumstances, and that the council can no longer justify insisting on restoration through Section 106 planning conditions.

“The application has only just been submitted and public consultation is currently underway. No assessment has yet been carried out by the council regarding its acceptability.”