An onslaught of development battles poses the greatest threat to the landscape of Hampstead and Highgate in history according to two prominent conservation societies – in what has been dubbed a “planning apocalypse”.

A flood of controversial planning proposals unveiled this week, on top of ongoing fights over Athlone House, the Hampstead Heath dams project and HS2, have prompted the bleak warning from the Heath and Hampstead Society and the Highgate Society.

Both are embroiled in fighting complex planning wars on multiple fronts and they have vowed to combine forces to protest against future developments.

It comes as Sainsbury’s faces a massive backlash over plans for a new store in a shopping parade on the edge of Hampstead Heath, sparking the anger of Bill Oddie, Dame Janet Suzman and hundreds of others.

The retail giant plans to convert four independent shops in South End Road into a Sainsbury’s Local, leading residents to label the company “Painsbury’s” and issue the demand “Don’t mess with Hampstead!”.

In Highgate, the fight to stop the demolition of historic Athlone House, on the edge of Hampstead Heath, moved up a notch as the Highgate Society began fundraising for a legal challenge.

Highgate Society vice-president Michael Hammerson said civic groups were facing a number of controversial planning bids.

“In terms of the scale and seriousness of the threat, it is as serious a situation for the local area as we have ever had,” he said. “It is a planning apocalypse.”

Both societies hope that working together will help to meet the threat head-on.

Heath and Hampstead Society chairman Marc Hutchinson, 59, said: “When two societies combine the opposition is going to be much more effective.”

Senior members of the Highgate Society say they will be forced to rely on public donations to fund a costly legal fight over Athlone House. The looming legal battle comes as the society plunges existing finances into a legal challenge over the Hampstead Heath dams project and an appeal against plans to build luxury homes on the Highgate Bowl.

“The outcomes are so serious and fundamental for the future of our area that we have to throw everything at them,” Mr Hammerson said. “The pressure is enormous at the moment and it’s not just these two appeals.”

Heath and Hampstead Society trustee Douglas Maxwell, an architect who lives in Hampstead Village, added his voice to fears that the unique village characters of Hampstead and Highgate are under immense threat.

“I think the situation is very serious,” he said. “We encourage those who think the same to support us both by joining the society and by helping us in this work.”