A county council has been criticised over the destruction of the landscape around one of Britain's major prehistoric sites.
Opponents say the plans threaten the 'Stonehenge of the North'
Thornborough Henges, near Ripon, has the greatest concentration of late Neolithic and early Bronze Age sites in the UK.
It also boasts the country's largest quarrying operation on prehistoric land, Nosterfield Quarry, producing more than 500,000 tonnes of sand and gravel each year.
Construction firm Tarmac is planning to extend its activities in the area as supplies from existing reserves are expected to run out within three years.
Archaeologist Dr Mark Horton, a presenter on the BBC's Time Flyers programme, criticised North Yorkshire County Council over the destruction of the landscape around the site.
Dr Horton, head of archaeology at the University of Bristol, said: "I've been appalled by what I've seen at Thornborough.
"Archaeological sites like this should be protected and plans such as these shouldn't even be proposed.
"That such landscape destruction could even be considered around Stonehenge, or even our lesser-known sites in the south, is unthinkable.
"Yet at Thornborough it is OK to seriously consider the total loss of a
prehistoric landscape, arguably as important, for simple economic gain."
North Yorkshire County Council permitted Tarmac to quarry in the area in 1994 after "only a very limited archaeological survey", Dr Horton said.
But county council archaeologist Neil Campling defended the previous studies that had been carried out and said all the finds had been recorded properly.
In the event of an official planning application being submitted, a
review of the environmental impact of the plans would be carried out, he said.
And a Tarmac spokeswoman denied the site was under threat
"The Thornborough Henges site is an important site of archaeological interest and we believe that in Tarmac's care, it is in safe hands," she said.
"There are no plans to dig up or destroy the henges and we would restore the site in consultation with archaeological experts and provide a visitor centre."