Plans to put the A303 past Stonehenge into a tunnel almost two miles long have been hailed as a "truly momentous decision" for the heritage site.

Ministers have announced moves to tackle congestion on the A303 as it passes the World Heritage Site - a notorious bottleneck on a major route to the South West - including putting the road into a 1.8-mile (2.9km) dual carriageway tunnel past the landmark stones.

The £2 billion scheme was welcomed by English Heritage, which looks after the stone circle, and the National Trust, which owns much of the land in the wider World Heritage Site.

Although the stones will no longer be visible to motorists driving past, the tunnel will reconnect Stonehenge with two-thirds of the World Heritage Site that lie to the south of the A303 and are currently cut off by it.

The heritage groups said the tunnel would make the setting of the stones more tranquil, give the public greater access to the wider prehistoric landscape and improve the environment for wildlife.

It is the latest attempt to improve the setting of Stonehenge, one of the UK's most famous heritage sites with more than a million visitors a year, in a saga that has rumbled on since it became a World Heritage Site three decades ago.

A 1.3-mile (2.1km) tunnel was proposed a decade ago, but the plan was abandoned amid spiralling costs in 2007. Last year, the A344 just past the stones was closed and facilities relocated to a new visitors' centre some 1.5 miles (2.4km) away.

Officials attempted to resurrect the 1.3-mile tunnel as an option for tackling the A303 bottleneck earlier this year, but English Heritage and the National Trust rejected the plans as "unacceptable".

They proposed longer tunnel options which would take the road out of more of the World Heritage Site, reduce the impact of the tunnel's exits and entrances and move them further away from ancient burial sites, or barrows, which dot the landscape.

In response to the Government's announcement, Helen Ghosh, director-general of the National Trust, said: "After many false starts and challenges, this does for the first time feel like a real opportunity to tackle the blight of the road that dominates the landscape of Stonehenge.

"If designed well, putting the A303 into a tunnel of 2.9km will bring the Stonehenge landscape together once more, creating space for nature and improving the site's tranquillity.

"I know there will be some sadness that people will no longer be able to see the stones from the road, but visitors will once again be able to hear the sounds of skylarks singing rather than the constant noise of traffic.

"We're committed to finding alternative ways for even more people to see the stones on their journey and for future generations to experience and explore this inspiring prehistoric landscape as our ancestors did."

Dr Simon Thurley, chief executive of English Heritage, said: "This will be the biggest single investment ever by Government in this country's heritage and is truly a momentous decision.

"We felt so proud to close the A344 last year and build award-winning visitor facilities at Stonehenge.

"We have been campaigning for a tunnel to remove the blight that is the A303, for the past 30 years. This news is the icing on the cake and vindicates all our hard work."

He said any new scheme to put the A303 into a bored tunnel must be located in the right place and be well designed.

The CBI has also welcomed the Government’s announcement of a five-year Road Investment Strategy, which includes the commitment to build a tunnel underneath Stonehenge.

John Cridland, CBI director general, said: "This five-year strategy marks a significant milestone in our journey towards the delivery of much-needed upgrades to our existing road network, the arteries of our economy.

“I’ve been calling for a tunnel underneath Stonehenge as part of wider upgrades along the A303, a lifeline for businesses in the South West, so I am glad to see it getting the green light.

“It is essential now that we see a commitment from all sides to take this programme forward in the coming Parliament, shifting our focus towards delivery.

“Our recent infrastructure survey showed how important infrastructure is to UK businesses, but with 57% fearing transport links could worsen in the next five years, now is the time for action."