PRICELESS archaeological treasures and natural habitat is being destroyed by arsonists on an ancient hill fort, a campaign group is warning following a large blaze on Friday.

The Eston Hills area has been plagued by vandals and arsonists in recent years but incidents dropped last year due to a joined-up effort between the police, fire brigade, Redcar & Cleveland Council and the Friends of Eston Hills Group on a task force.

The Ice and Fire project, which is digging up treasures dating back to Neolithic times – just after the Ice Age – on the historically precious site, has also been running education programmes to teach children how important the site is.

But a large fire broke out on the hills at about 11pm on Friday. Locals reported groups of youths drinking in the area.

Spencer Carter, one of the archaeologists who runs the Ice and Fire project, along with Adam Mead, said there was 10,000 years of history on the site, with recent finds including tools, evidence of the first farmers, and nomadic groups from after the Ice Age.

He said the fires are devastating and risk damaging ancient treasures as well as a natural habitat around the wetland known as Carr Ponds.

"The arsonists are not just kids," he said. "People buy old 4x4s, fill them up with petrol and take them up there until they run out of petrol. That coupled with quad bike riders are churning up the land. Often the 4x4s are set fire to once they run out of fuel.

"The site up there is precious and once it has gone, it has gone. This is all irreparable, priceless stuff.

He said there had been firearms incidents on the hills, with farmers' livestock being killed, as well as the arsonists.

Rita Richardson, of the Friends of the Eston Hills, said: "They are our hills, they belong to the community, and we are trying so hard to educate people to take care of them. We are devastated by this latest fire because it had been going so well."

She said she had asked Redcar MP Anna Turley, who has been supportive of the project, for a meeting next week to try and find a way forward.

The council has put up fences and gates to try to prevent vehicles entering the site and has to remove vehicles frequently.

The Eston Hills area is home to an Iron Age Hill fort and Bronze Age burial mounds.