They are a disparate bunch. Archaeologists, environmentalists, historians, transport experts, countryside campaigners and druids.

But they will come together in the Strand in central London on Tuesday with a common purpose: to stop the bulldozers from, in their mind, wreaking havoc at one of the UK’s most iconic sites.

They will try to convince the high court over three days that the government’s plan to build a two-mile road tunnel close to the great circle of Stonehenge will permanently disfigure a unique and globally important landscape.

“It’s David and Goliath stuff,” said John Adams, the chair of the Stonehenge Alliance, which has fought against the tunnel and other road projects around the stones for more than 20 years. Though lots of disciplines are represented, they lack the heft of the government machine. “We’re up against the might of the Department for Transport, National Highways and so on. We’re a small organisation – mostly retired people. But the court case is critical. It’s the only thing keeping the earth diggers away,” he said.