A petition with thousands of signatures calling on the Government not to damage the Stonehenge landscape with road plans has been handed into Downing Street.

Historian, author and broadcaster Tom Holland warned that plans to upgrade the A303 through the World Heritage Site would be “calamitous” as he led a group of campaigners to hand in the petition.

The proposed upgrade includes a 1.8-mile long tunnel to restore the tranquil setting of the stones, but would see tunnel entrances and a new dual carriageway within the archaeologically rich World Heritage Site.

The road, which currently passes the stones, often suffers from severe congestion as it is a popular route for motorists travelling between London and the South West.

Campaign group the Stonehenge Alliance has gathered around 50,000 signatures for its petition calling for “no further damage” to be done to the archaeological landscape in which the Neolithic stone circle stands.

The petition has been handed into 10 Downing Street, addressed to the secretaries of state for transport and culture.

It says that if the A303 widening at Stonehenge is felt to be essential, it should be done by means of a deep bored tunnel at least 4.5km (2.8 miles) long, as anything less would cause “irreparable” damage to the wider World Heritage Site.

A fifth of the signatories are from more than 100 countries outside the UK, which organisers say underlines international concern over the project expressed by Unesco’s World Heritage Committee, which has opposed the road in its current form.

It’s a complete farce to expect to solve congestion and preserve the site by building a huge new expressway there

Sir Tony Robinson

The alliance also says the project is poor value for money and does not take into account climate change.

Mr Holland, president of Stonehenge Alliance, said: “We’re talking about our most iconic, precious and archaeologically significant landscape; a landscape that has a significance that has been internationally recognised, and legally recognised by Unesco.

“That imposes a legal obligation on the Government to respect that.”

The Government cannot dig up and despoil a landscape that has been there for millennia, with four-lane highways, tunnel portals and slip roads and potentially damaging the water table that protects important archaeology, he warned.

“It’s a calamitous act of desecration,” he told the PA news agency.

Campaigners warn against going ahead with the A303 plans (Stefan Rousseau/PA) Credit: Stefan Rousseau

Asked if he thought Boris Johnson would listen to concerns over damage to the site, he said the PM had a love of infrastructure projects but also of antiquity.

“I hope his love of antiquity will outweigh his love of sending in the bulldozers,” he said.

Sir Tony Robinson, Time Team presenter and campaign supporter, said: “The impact of building huge new roads into the Stonehenge Neolithic and Bronze Age landscape would be dire.

“It’s a complete farce to expect to solve congestion and preserve the site by building a huge new expressway there.”