The government may be forced to rethink its plans for Stonehenge, abandoning the proposed new visitor centre and building a far longer and more expensive road tunnel under the site, following publication of a much delayed management plan.
Successive governments, English Heritage, which owns the stones, and the National Trust, which owns thousands of surrounding acres, have been struggling for 20 years to resolve the problem of Stonehenge, where the visitor facilities have been condemned by the Commons public accounts committee as "a national disgrace".
The plan's emphasis on the importance of the entire site, not just the area around the stones, could cause havoc for the highways agency, which may be forced to rethink its proposed road tunnel across the site. Both government and local authorities are bound to consider the management plan in all future planning decisions.
The management plan has been prepared for the government by an expert committee, after a public consultation process. It was required to produce the plan by Unesco as Stonehenge is ranked among the most valuable and sensitive sites in the world, along with the Taj Mahal and the pyramids.
Archaeologists and environmentalists welcomed the plan as their best weapon yet against the highways agency proposals. The agency is proposing a two kilometre tunnel, with entrance portals outside the saucer-shaped plain around the stones, but still within the world heritage site.
The objectors are demanding a tunnel twice as long, which would pass under the entire site. They are also demanding a bored tunnel, instead of the highways agency's cheaper "cut and cover" version, involving digging a trench across the landscape and then filling it in over the tunnel roof.
The highways agency estimates its tunnel at £125m, and the bored tunnel at £300m.
The management plan does not explicitly back the long tunnel, but repeatedly stresses the unique importance of the entire site, a 5,000-year-old ritual landscape littered with thousands of ancient monuments apart from the stone circle.
The plan backs proposals to return the land to open chalk downland grazing, and says that farmers will have to be compensated for abandoning arable farming and deep ploughing.
It also stresses that the site must be protected from noise and light pollution from traffic, which the objectors believe would be impossible with the shorter tunnel.
Local archaeologist Kate Fielden, who represented the Council for the Protection of Rural England at consultations on the plan, demanded yesterday that the road scheme, which she called "hugely damaging", should be abandoned.
The plan may also force reappraisal of the location of a proposed new visitor centre. It says that profits from a "world class" centre should be spent on managing the site, which almost certainly kills off the chances of a major commercial operator taking it on.
A source in the Stonehenge management group said the plan would place such tight restrictions on the visitor centre, and the possible profits, that it was "highly unlikely" any commercial operator would take it on. It is believed that several potential operators, including the Tussauds group, have examined the proposals and concluded that the sums do not stack up.
Geoffrey Wainwright, former chief archaeologist at English Heritage, and a member of the Stonehenge steering group, said yesterday: "At last we have agreement, after dozens of site visits, months of consultation with all the interest groups, four drafts and some pretty major amendments. We now have a consensus on how to proceed."
A spokesman for the highways agency said the road proposals were still at "a very early stage". Consultants were appointed in March to produce detailed plans by 2002, with construction hoped to begin in 2005.
