Campaigners against the Hampstead Heath dams project are urging the public to raise their objections with planning chiefs before it is too late.

Members of the Dam Nonsense opposition group, who are fighting the £15million proposals, warned there is now “one week to save Hampstead Heath” ahead of the imminent deadline for comments on the planning application.

Responses to Camden Council’s planning consultation must be made by Thursday (August 7).

Marc Hutchinson, chairman of the Heath and Hampstead Society, which is leading the Dam Nonsense campaign, said: “These engineering works are the greatest threat to the historic landscape of the Heath since the London County Council tried to turn it into a park in the 1890s.

“The society urges all those who want to preserve the landscape to oppose the planning application, which is based on a mistaken view of reservoir law and an extreme and irrational approach to flood risk.”

Meanwhile, the Heath and Hampstead Society is due to formally launch judicial review proceedings this month, after the City responded to a pre-action letter.

The City of London Corporation, which runs the Heath, wants to enlarge or build new dams and spillways across the Heath.

Its aim is to “virtually eliminate” any possibility of the dams collapsing, even in the maximum theoretical flood which is estimated to happen once in 400,000 years, and has been described as a “biblical storm” by critics.

The City insists the scheme – which would see up to two years of construction work, engineering vehicle movements and pond closures on the Heath – is required by law and could save up to 400 lives.

A previous public consultation, run by the City rather than Camden Council, has already been met with an overwhelmingly negative response, while more than 5,000 people have so far signed a recently-launched petition against the project at you.38degrees.org.uk/p/damnonsense.