A £27million project to improve Stonehenge is due to begin today.

The redevelopment will see part of a main road closed and grassed over, the car park and fences near the monument moved and a new visitor shuttle introduced.

A large exhibition will tell the story of the stone circle and its relationship with the wider landscape and will feature items excavated nearby.

English Heritage has been planning improvements to the historic site since the 1980s.

In 1993 the Public Accounts Committee of the House of Commons described the situation as "a national disgrace" due to inadequate facilities and a cluttered landscape.

The section of the A344 which currently runs past the landmark close to the Heel Stone will be closed and grassed over as part of the overhaul, allowing the reintroduction of an ancient processional route to the stones.

The remaining part of the road will be closed to public vehicles and will become the route for the shuttle service to the stones.

Visitors to the ancient stone circle will arrive at new facilities at Airman's Corner and approach the cluster on the shuttle or on foot over chalk downland, rather than the current busy road and a new visitor building will feature education rooms and improved amenities.

The revamp is expected to take just over a year.

Dr Simon Thurley, chief executive of English Heritage, said: "A new dawn at Stonehenge is truly upon us.

"Though the stones themselves have never failed to awe visitors their setting has been a national embarrassment and disgrace.

"After nearly 30 years English Heritage finally has a scheme that will transform the setting of the stones and our visitor's experience of them.

"The restoration of the landscape together with a major new exhibition on site will finally give our greatest and most famous monument the treatment it deserves.

"Stonehenge is a national icon and this project will finally make it worthy of that status."

John Penrose, Heritage and Tourism Minister, said: "People have been talking about the project for nearly 30 years and so I'm absolutely delighted that work is finally under way to preserve this internationally recognisable prehistoric World Heritage Site, and to improve the visitor experience for those who come to marvel at it too.

"I'd like to congratulate everyone involved in making it happen at last, and I look forward to seeing the new visitor experience in just over a year's time."

The project has been developed with the support of the National Trust, Wiltshire Council, the Highways Agency, and Natural England and has been financed by Heritage Lottery Fund money, commercial income and philanthropic donations.

English Heritage still needs to raise £500,000 of the project costs, the charity has said.

Work on the new exhibition and visitor building will begin today (Wednesday) and the Highways Agency will start work to upgrade Longbarrow Roundabout in September before the closure of the A344 in April 2013.

Stonehenge will remain open to visitors and an opening date for the new building will be announced in 2013.