An imminent legal battle over the Hampstead Heath dams project is of “national importance” according to the scheme’s opponents.

The Heath and Hampstead Society is set to challenge the £15million scheme by judicial review after the City’s Hampstead Heath, Highgate Wood and Queen’s Park Committee approved the plans on Monday (June 9), with only one member voting against.

The society believes it will become a “test case” that could determine how reservoir laws are interpreted and how they apply to smaller water bodies, like the Heath’s ponds, across the country.

Marc Hutchinson, secretary of the society, said: “It’s of national importance as well as just for Hampstead, so we would hope the judge would agree it’s a case that should be heard.”

The City looks set to defend the scheme in court despite appearing to admit that it would be in its own interests to lose the case.

At a fiery public meeting last Thursday (June 5), Philip Everett, the City’s director of the built environment, admitted that a judge’s ruling that the project need not go ahead would be gladly received.

After repeatedly being asked if he would “welcome” such a decision by the High Court – which would save the City £15million and spare it from widespread public criticism – he finally responded with a resounding “yes”, prompting huge cheers from the hall.

Mr Hutchinson said: “It would save the City a lot of money. The society has been saying for the last two years that it must be in the City’s interest to find a way not to carry out the works on this scale.”

The public meeting was hosted by Camden Council at Parliament Hill School in Highgate Road and saw residents grill representatives from the City and its contractors Atkins and BAM Nuttall.

The audience of hundreds appeared to be almost unanimously opposed to the scheme, which critics say will “permanently disfigure” the green acres.

“We feel that Camden Council were left in no doubt as to the general public hostility to this entire project,” added Mr Hutchinson.

The project would see dams enlarged by up to 18ft, with major changes including a new embankment to be built across the “catchpit” valley, north of the Hampstead chain of ponds, and drastic changes to the Model Boating Pond in Highgate, which would be much larger with a tree-studded island in the middle.

The City claims the work is required by reservoir legislation. The Corporation also believes it will be liable for any deaths contributed to by the collapse of the dams if it does not act, estimated to be as many as 300 in the most extreme storm.

It plans to submit a planning application to Camden Council in July.