Controversial drilling on Hampstead Heath has been postponed to avoid disturbing swans, coots and blue tits during nesting season – to the relief of campaigners who opposed the work.

Ham & High: Drilling technicians use a cable percussion rig to take soil samples between the Kenwood Ladies' Bathing Pond and the Bird Sanctuary Pond. Picture: Polly HancockDrilling technicians use a cable percussion rig to take soil samples between the Kenwood Ladies' Bathing Pond and the Bird Sanctuary Pond. Picture: Polly Hancock (Image: Archant)

Engineers have been on site to examine the Heath’s soil in recent weeks, using heavy machinery to bore dozens of holes between three and 15 metres into the earth.

The project had riled wildlife enthusiasts who were angry it was being carried out during nesting season, which runs from March 1 to July 31.

They even reported the matter to the Metropolitan Police’s wildlife unit, claiming the work would breach laws which prohibit disturbing nesting birds.

But the City of London Corporation, which runs the Heath, has now delayed some of the drilling to protect several nests.

The news has been welcomed by critics. Hampstead Garden Suburb resident David Lewis, who made the police report, said: “I’m pleased to her that someone’s been watching this and they have not disturbed any birds.

“Most authorities just ignore these regulations.”

Workers will return in August, after the nesting season has finished, to take more samples at the Hampstead No 1 Pond, the Stock Pond and the Catchpit.

A spokesman for the City of London Corporation, which runs the Heath, said: “As it was nesting season, our ecologists and Bam Nuttall’s [the City’s contractor] environmental team have been out on site every working day, checking the sites carefully.”

The ground investigation programme was being carried out in preparation for the much-criticised £15million ponds project.

The City’s spokesman added that the engineers have so far found plenty of clay in the ground, which is what they hoped for.

“This is good news for the construction of the new dams and it means we are able to find a lot of the material required on site,” she said.