The A303 next to Stonehenge frequently experiences high levels of traffic Getty

Blackadder actor and Time Team presenter Tony Robinson has voiced his concern at the proposals to build a tunnel underneath Stonehenge after plans were approved by the government in the hopes it will reduce congestion and noise around the historic site. The Department for Transport confirmed the A303 will be "transformed" as part of a £2bn ($2.4bn) investment in the south-west in January.

The plans include expanding the seven-mile single carriageway stretch of the A303 near Stonehenge in Wiltshire into a 1.8m (2.9kn) dual carriageway to improve the high levels of congestion in the area.

The idea for a tunnel underneath the World Heritage Site has been backed by the owners the English Heritage and National Trust as it will reduce traffic pollution and noise for those visiting the world-famous landmark.

However, historian Tom Holland, of the campaign Group the Stonehenge Alliance, described the government's decision as "calamitous".

He added: "It threatens untold damage to the most significant prehistoric landscape in Europe, and risks annihilating sites that promise to open a window onto the very beginnings of Britain.

"A Conservative Government should properly be conserving what is most precious about our country, not destroying it."

An online petition against widening the A303 set up by the Stonehenge Alliance has attracted more than 22,000 signatures.

Robinson has also voice his concern at the plans to build a tunnel close to the site. He said he will join a planned protest by the Stonehenge Alliance at the Society of Antiquaries at Burlington House, during Highway Agency consultation on the issue which will continue through to MarchTim

Robinson said: "The primary criterion if road widening or tunnel building are required, must be that no further damage is done to this very special landscape."

Fellow historian Dan Snow, president of the Council for British Archaeology (CBA) , also said the plans to build near Stonehenge "endanger this unique site". He added: "We have recently started to realise that the standing stones are just a beginning. They sit at the heart of the world's most significant and best-preserved stone-age landscape.

"Around the world we see pictures of our fellow humans smashing the treasures of the past and count ourselves lucky that we live in a country which values its rich history and appreciates what it offers modern Britain. Our heritage helps us understand ourselves, how we got here and where we are going."

Tony Robinson
Actor Tony Robinson is also against the plans Getty

CBA Director Mike Heyworth, added: "These proposals are the latest in a long-running saga, but need to be considered carefully as any damage to the internationally significant prehistoric landscape around Stonehenge is irreversible. CBA trustees will consider the proposals in detail before reaching a conclusion."

The government said drivers and local residents will be able to have their say on the proposals, with a consultation running between 12 January and 5 March. The preferred route is set to be announced later in 2017.

Secretary of State for Transport Chris Grayling said: "This government is taking the big decisions for Britain's future, underlined by our record £15bn funding for road schemes.

"This major investment in the south-west will transform the A303 and benefit those locally by cutting congestion and improving journey times. It will also boost the economy, linking people with jobs and businesses with customers – driving forward our agenda to build a country that works for everyone and not just the privileged few."

Highways England Chief Executive Jim O'Sullivan added: "We are delivering the biggest investment programme in our roads in a generation.

"Our plans for the A303 recognise the national importance of the route and these improvements will bring real benefit to the region and local communities. The public exhibitions will provide an excellent opportunity to explain further our plans and to hear feedback from stakeholders on our proposals to deliver the scheme."

This article has been updated on 8 February to include Tony Robinson's statement.

Traffic passes along the busy A303 that runs besides the ancient neolithic monument of Stonehenge Getty