Stonehenge may be placed on the list of endangered World Heritage sites after the Government abandoned all the options it was considering for relieving congestion on the road that runs past it.

It means the site will be blighted indefinitely by heavy traffic on the A303, which passes close to the stones.

Despite spending more than £23 million over ten years on developing proposals, the Government decided that the various alternatives, including turning the road into a dual carriageway and burying it in a tunnel, were either too expensive or unacceptable on environmental grounds.

Unesco, the United Nations cultural body, said that it would consider placing Stonehenge on its endangered list when the World Heritage Committee met in Montreal in July. It expressed disappointment that nothing was to be done to solve the problem although it had told Britain that it must take action over the heavy traffic when it awarded Stonehenge World Heritage site status in 1986.

Tom Harris, the Transport Minister, said that the cost of the proposed 2.1km (1.3 mile) bored tunnel scheme had soared from £223 million to £540 million. He said that allocating such a sum “cannot be justified and would not represent best use of taxpayers’ money”.

He also ruled out other options that would have taken the A303 well to the north or south of the stones, on Salisbury Plain, Wiltshire. At present, the A303 runs 150 yards from the stones. It is one of the few remaining single-carriageway sections of the key holiday route to Devon and Cornwall and is heavily congested in the spring and summer.

The Government’s decision also means that English Heritage, which owns the site, has had to cancel plans for a £67 million visitor centre.

The decision was preceded by a furious row behind the scenes between the Department for Culture, Media and Sport (DCMS), which believed that the tunnel should still be built despite the cost increase, and the Department for Transport, which has been hit by a series of cost escalations on road-building projects.

English Heritage said that it was “very disappointed” by the decision. “This signals the end of the project championed by the DCMS and English Heritage over the last eight years which sought to improve both the landscape setting of Stonehenge and the visitor experience. The project, collectively decided upon by a range of national and regional stakeholders, was the best and most practical means by which the agreed vision for the Stonehenge World Heritage Site could have been achieved.”

The decision was welcomed by environmental groups, which said that the tunnel would have scarred the landscape. Denise Carlo, of the Campaign for Better Transport, said: “The plan to build a tunnel and road through the Stonehenge World Heritage Site would be an environmental and financial disaster. We’re glad the Government has seen sense to drop this brutal scheme.”

Save Stonehenge!, a campaign group, said that only a 1.3mile section of the proposed 7.7mile route would have been underground and that the decision was “the only sensible outcome as a massive road-building project was always the wrong solution in such a sensitive landscape”.

A spokesman added: “No one with any sense wanted a tunnel, a flyover, a dual carriageway, and two whacking great interchanges here. It’s just not acceptable to build 1950s-style motorways in places like this any more.”

Mr Harris said that the Highways Agency would investigate possible small-scale improvements to the A303 and would also consider closing the junction of the A303 with the A344, which runs just a few yards from the stones.

Theresa Villiers, the Shadow Transport Secretary, said: “A solution is further away than ever despite £23 million having been spent on preparations for a tunnel which is no longer going to be built – yet more broken promises on roads and yet another let-down for thousands of people frustrated by congestion on the A303. The Government’s complete failure to tackle this problem is becoming a national embarrassment.”

Milestones

1989 Commons Public Accounts Committee described the setting of Stonehenge as a “national disgrace”

1991 Department for Transport began considering options for relieving traffic 50 options considered for solving the problem

2007 Government cancels all the options for improvement

Sources: Highways Agency; Save Stonehenge; Times archives

Editor's choice

• The 100 Best Films of the Decade
• 70 facts you didn't know about Marvel
• The 50 Biggest Movies Of 2010