Such a move would intensify pressure on the Department of Transport to use tunnels to limit damage from other controversial schemes, including the east London river crossing route, which will destroy part of Oxleas Wood in south-east London.
Ministers who support tunnelling are treading warily. It would almost double the cost of the pounds 28m dual-carriageway A3 scheme, but would answer growing criticism that the Government is using its powers, unchecked, to press on with road plans against the wishes of local people.
The Government rejected a cut-and-cover tunnel for Oxleas Wood, which would have cost proportionally much less than the one under consideration for the A3, even though the public inquiry inspector recommended one be dug.
John Major is under fire from government advisers for not doing more to protect the environment.
The countryside around Hindhead lies within a designated area of outstanding natural beauty. More than 1,400 acres of Hindhead Common including the Punch Bowl, a steep depression, is owned by the National Trust. The land is a site of special scientific interest.
The original Department of Transport route runs on an embankment, along the side of a valley to the west of the Devil's Punch Bowl, before swinging eastwards to pass through a ridge in a cutting up to 7 metres (23ft) deep. The department admitted that the route would cut across the northern end of the Punch Bowl 'creating some severe local impacts'.
A review of the plan a year ago led Malcolm Rifkind, then Secretary of State for Transport, to say he was considering adopting an alternative route. That would cross Hindhead Common, mostly in a cutting, and swing north to pass through the rim of the Punch Bowl in a cutting up to 15 metres deep, to join the existing A3 at Gibbet Hill.
The department said it would take about 72 acres (29 hectares) of the site of special scientific interest, affecting heathland on Hindhead Common, home to a colony of sand lizards, a protected species. There would be a 'moderate impact' on the landscape.
John MacGregor, the Secretary of State for Transport, sought further local consultation on the two routes in August.Reuse content