PROTEST group the Stonehenge Alliance has made an impassioned case against the plans for a dual carriageway and 2.1km tunnel through the World Heritage site, branding it "short sighted" and "short-lived".

The organisation, which is a collaboration of environmental and archaeological groups, said the proposals would leave a deep scar on the landscape and divide the world-famous site in two.

They argued that less than 20 per cent of the new road would be hidden in a tunnel, while the remainder of the busy stretch would be bulldozed at ground level or in deep cuttings, causing damage to other significant monuments.

Last week, the campaigners urged public inquiry inspector Michael Ellison to recommend the shorter tunnel be shelved until funds could be raised for an alternative scheme that hid the road completely.

Opening their case, George McDonic said the Highways Agency proposals were in breach of planning guidance and policy because they did not protect the integrity of the site.

He added that the tunnel was unlikely to solve the traffic problems near Stonehenge that make life a misery for motorists.

"The transport benefits of the published scheme are likely to be short-lived and the short-bored tunnel would, in due course, become a new bottleneck," he said.

"The government's transport policy since 2002 recognises that congestion will not be solved by road building alone."

Despite reassurances from the Highways Agency that the environmental impact of the scheme has been fully investigated, the protesters remain unconvinced.

"The visual and sensual damage to the World Heritage site and the nearby countryside and their settings would be unacceptable," said Mr McDonic. "This length of road would be a substantial barrier between those parts of the World Heritage site lying to the north and those to the south of the A303.

"The decision-makers need to recognise the importance of not accepting a solution that seems affordable today but within a short period of time would be seen as seriously damaging the area it sought to protect and enhance.

"With the right scheme, it would be possible to restore the integrity, tranquillity, settings and unification of the whole site.

"The Stonehenge Alliance believes the government should reject this scheme and produce one which meets its international obligations and conforms to its own policies."

Stonehenge expert Dr Kate Fielden urged the inspector to recommend that ministers be patient.

"The government has rejected the longer tunnel, which was the earlier agreed best heritage road option for the Stonehenge World Heritage site, on the grounds of cost," she said.

"The balancing exercise has clearly been got wrong.

"More weight should be given to heritage considerations than to economic considerations.

"We must get things right at Stonehenge.

"If it is too expensive to do that now, we must wait until the money is available, or raise the money needed from other sources."