Skyscrapers could be built on the outskirts of Hampstead Heath if a planned overhaul of the planning system is approved, critics have warned.

The government is consulting on sweeping proposals that will condense more than 1,000 pages of complicated planning policy into a single 52 page document and give all applications a presumption in favour of sustainable development.

But members of the Heath and Hampstead Society and the Highgate Society have both warned that if the policy is approved many unpopular developments fought-off by residents will almost certainly get the go-ahead.

Helen Marcus, of the Heath and Hampstead Society, said: “It is town cramming that is going to be awful. Garden grabbing is going to become far more common.

“And there is a specific threat to the Heath.

“Our society has spent the last 80 years preventing tall buildings encircling the Heath – you can stand in the middle of it, see for miles all around and feel like you are in the middle of the countryside.

“But if this goes ahead it will be harder to stop skyscrapers being built on its fringes and developments like number one Hyde Park.

“It is a sheer lie that this is going to give local people control. All we will be able to do is ask for new developments, not oppose them.”

Controversial plans to bulldoze Athlone House, a Victorian mansion on the fringes of the Heath, which were seen off by residents earlier this year would also be waived through if the changes are implemented, she added.

And plans put forward by developers of Fitzroy Farm in 2009 to use a path from Millfield Lane to the Ladies Pond on Hampstead Heath for heavy goods vehicles - which residents at the time likened to the “the slow lane of the M1” - may also have been harder to defeat.

Michael Hammerson, of the Highgate Society, said: “If you thought basement excavations are bad, you haven’t seen anything yet.

“There will be no way to stop someone building a huge back extension building on land at the back of a house. It will seriously weaken protection of our historic conservation areas.”

Both societies are urging residents to write to their MPs and councils to oppose the changes ahead of an expected ministerial decision at the end of the year.