Residents fear protected creatures have been “slaughtered” on land owned by Bath and North East Somerset Council – weeks after it declared an Ecological Emergency.

Its plans to build 37 homes in an Englishcombe Lane field were approved last month against the advice of the authority’s own ecologist. Promises were made to move the tufa springs, a rare habitat of county-level importance, to a separate site.

It was claimed the scheme would boost biodiversity – but residents say they recently witnessed the overgrown field being mowed, and fear this killed numerous slow worms, a protected species of lizard.

The Council has said it is investigating the incident, which has also been reported to the police, after photos were posted online this week by Iona Gorrie showing severed bodies of slow worms. She said on Facebook there had been an “enormous tractor with a huge plough” that had “slaughtered most, if not all of the slow worms” that had been caught in traps intended to move them to safety.

Danny Groves, who spoke out against the development, said: “The Council’s ecologist categorically objected and they completely ignored her.

“It was the first test of the Ecological Emergency and they went against it. If you aren’t committed, don’t say it.”

A spokesperson for B&NES Council said no developer had been officially appointed for the site: “We would expect all developers to abide by the rules and the Council will take appropriate action where they don’t, We are aware of the concerns raised on social media about the protection of wildlife and we are investigating the specific issues raised.”