Debris from a development site in Highgate spilled onto Hampstead Heath last week, sparking fury among residents.

Water and clay cascaded from a construction site on Fitzroy Farm onto a path on the Heath on Friday (June 15) at 2pm.

Builders sprung a leak after digging a borehole on the site of the new home, which when finished will feature a tennis court and slide for an indoor swimming pool.

James Crowley, 50, was walking home when he spotted the spill just metres from the Ladies Pond.

The resident of Holly Lodge Estate, in Highgate, said: “There was just a flow of something coming from the building site, across the lane and into the Ladies Pond.

“It’s outrageous to be honest for the building work to have such a destructive impact on the Heath.”

Danny Barrett, a builder working at Fitzroy Farm, said: “The ground water permeated its way up as we drilled a borehole into the ground. When this was combined with the freak storm we had a little earlier, it meant water escaped onto the path nearby.”

Lynn Fry, from neighbouring Fitzroy Park, said the whole area had been blighted with building work for years.

But Karen Beare, secretary of Fitzroy Residents Association, said the owners of Fitzroy Farm had been very sensitive to neighbours’ concerns.

She said: “The owners have acted impeccably. They have involved residents and been incredibly sensitive about the surrounding environment.”