Campaigners have this week launched their fight to save Hampstead Heath from “monumental engineering works” that many fear will disfigure the cherished landscape.

Ham & High: Tony Hillier, chairman of the Heath and Hampstead Society, at the Model Boating Pond. This view would disappear under the proposals. Picture: Nigel SuttonTony Hillier, chairman of the Heath and Hampstead Society, at the Model Boating Pond. This view would disappear under the proposals. Picture: Nigel Sutton (Image: � Nigel Sutton email pictures@nigelsuttonphotography.com)

The Heath and Hampstead Society tore into the case for major works at the treasured ponds at a packed public meeting to launch its Dam Nonsense Campaign on Monday.

The society won the backing of other pressure groups and hundreds of residents in calling for the City of London Corporation, which runs the Heath, to revise the controversial £15million scheme.

Lord Hoffmann, president of the Heath and Hampstead Society, issued an appeal for ongoing support in a fight that may lead to the courts, with the society vowing to seek a judicial review if the City ploughs on with the project.

He said: “The reason why we have called this meeting is to ask you to make it clear to the City that they will be extremely unpopular with everyone who loves Hampstead Heath if they do not make every effort to find a way of lawfully avoiding or reducing the damage to the Heath.”

The society officially adopted a resolution to urge the City to “revise their plans for the dams project so as to make the ponds safe without damaging the Heath”. The Corporation says the proposed works are mandated by reservoir laws, but campaigners are calling on the public body to join forces with them in seeking a court ruling that could make it clear that only lesser works are required.

Such a judgement would “save [the City] £15 million pounds and the ­unpopularity of having been the authority which disfigured Hampstead Heath”, Lord Hoffmann said.

The society has taken expert legal advice and has been told that its case is “clearly arguable” and has a chance of persuading a judge.

“What we cannot understand is why the City will not join with us in trying to get a ruling from the courts that we are right,” Lord Hoffmann said.

“If we and the City are unsuccessful in getting such a ruling, they will be in no worse position than they are now – and everyone will feel that they have at least done their best.”

The City wants to carry out works at every pond, most contentiously by raising a dam between the Model Boating Pond and the Highgate Men’s Bathing Pond by 8ft, and by increasing the size of an embankment above the Mixed Bathing Pond by 18ft.

The Corporation says nearly 1,500 people could die if the dams are breached in an extreme storm.

But Lord Hoffmann insisted the proposals go too far, because the City’s engineers are attempting to eliminate the threat posed by a flood of such unlikely severity that it is estimated to take place only once in every 400,000 years.

“We think that is not a rational ­approach and we don’t believe that is what parliament meant to happen when it passed the Reservoirs Act,” he said.

Drawing a parallel with the response to the 7/7 terrorist attacks on London, he said: “Transport for London could have considerably reduced the risk of it happening again by having security inspections at Underground stations like they have at airports, or prohibiting people from taking luggage on the buses or underground.

“But they didn’t do so, because in terms of inconvenience to the public, the cost would have been too high... even though the risk was a very clear one to human life, much greater than the risk of a storm which might happen once every 400,000 years.”

Lord Hoffmann also argued that the City’s engineers are ignoring the fact that an extreme flood would not come without warning.

“Boroughs like Camden are obliged by law to have a flood warning system in operation, but that has not been taken into account,” he said. “The engineers say that does not matter.”

Lord Hoffmann’s speech was followed by expressions of support from residents and other groups, including many of the Heath’s pond associations.

Many residents of downstream areas such as Gospel Oak, which are said to be most at risk, voiced their opposition to the dam works. Others recalled the famous flood of 1975 – and said that was caused by sewers backing up, rather than any breach of dams.

The “urban myth” of a death in the flooding was dismissed by the society’s vice president Helen Marcus, who said that she has done extensive research and found no reliable reports. David Lewis, of the Protect Our Ponds Campaign, said there has not been a death caused by a dam collapse in the UK since 1925.

Speaking after the meeting, Heath and Hampstead Society chairman Tony Hillier said: “We’re dealing with the greatest threat to the Heath since the society was formed in 1897. What we have learned tonight is that there’s huge support for our position.

“I think there is a tangible possibility [of the City listening].

“We have convincing arguments and there’s no reason to believe it isn’t going to get through to the decision makers at the City.”