THE Deputy Prime Minister Nick Clegg was at Stonehenge this morning to announce the long awaited £1.1billion tunnel under Stonehenge as part of one of the biggest road building plans in living memory.

It is hoped that the 2.9km tunnel will reduce congestion on the A303 which narrows to a single lane as it passes the ancient monument and return the World Heritage Site back to nature.

Mr Clegg said: ““The A303 as anyone who lives in the South West knows is a very important route and it is blighted by bottlenecks.

“The traffic slows to a walk past the stones and we do not just want to rebalance the books we want to rebalance the British economy and that means linking different parts of the country.

“The money is not only there but we are going to legislate on it and it will become part of law.”

It ends years of campaigning from local politicians and residents who have long called on the government to remove bottleneck. Plans for a 2.1km tunnel were shelved only as recently as 2007.

The MP for Salisbury John Glen said: "For many locally this news will be enthusiastically welcomed after years of traffic jams, delays and chaos caused by numerous road traffic accidents as well as the disruption of lorries thundering through Winterbourne Stoke.

“I pay tribute to Cllr Ian West, my predecessor Robert Key and local campaigners who have worked on this campaign over many years.

"However, as I said in my Westminster Hall debate in March, it seems quite clear that a tunnel is the only deliverable option.”

It is part of what is being described as the “Heineken budget” from chancellor George Osborne who in investing substantial money into marginal constituencies outside the major cities ahead of the election next May.

Despite the fact it was announced by the leader of the Liberal Democrats the local party remain sceptical about the project and have called for a local referendum something that was ruled out by Mr Clegg.

The parliamentary candidate Reeten Banerji said: “We are not keen that the tunnel plan is being linked with improvements to the whole A303.

“We would like the money to be used for road improvements all the way from Somerset to Amesbury. We suspect that linking the money is going to be a reason to kick the entire project into the long grass.

“The local Liberal Democrats are going to stand up to the national party and would like to see the tunnel option on a local referendum with other alternatives.”

It was also backed by the National Trust who were opposed to the previous tunnel on the grounds that it was cut and cover which might have damaged the site.

The institution - which owns 2,100 acres of countryside surrounding the stones - hope that the tunnel will open up two thirds of the site that is currently inaccessible and have called it a “world class solution for a world class site”.

Cassandra French, senior project manager for the National Trust, said: “This is all part of the broader community vision to be getting more local people to enjoy this wonderful landscape.

“We are currently at a moment in time. A lot of money is being invested and we have a brilliant opportunity to get this right.”