An enquiry into the £185m plans which would replace two existing roads near Stonehenge with a tunnel to ease congestion and remove cars from the vicinity of the site, has begun at Salisbury’s Guildhall.

The intended scheme would see the A303 re-routed and widened beneath the famous stones in a 1.3 mile-long tunnel.

Although English Heritage, the keeper of the monument, says that the removal of the roads would be the ‘crowning achievement of the Stonehenge project, enabling people to enjoy its landscape safely and at peace’, campaigners have protested that the plans would ‘scar’ one of the world’s most valuable treasures.

Last week, members of Salisbury District Council’s northern area committee voted against the plans, calling them ‘totally unacceptable’.

The enquiry, headed by an independent planning inspector, will listen to dozens of objectors, including Friends of Earth and Icomos, an international body representing conservation experts.

Many campaigners claim the tunnel is too short, and should be increased to at least 2.5 miles in order to bypass the numerous paths and ceremonial spaces that surround the stone circle.

Icomos earlier released a statement, saying: “Short-term priorities such as easing traffic congestion are given undue influence in the plans. A long-term view should be taken and a longer tunnel considered.”

Martyn Heighton, a spokesperson for the National Trust, said: “This public enquiry needs to consider whether the proposed tunnel is long enough to conserve and enhance the spirit of place, landscape and archaeological interest of Stonehenge.”

The enquiry will only be able to record and make recommendations to the minister of transport, Alistair Darling and the deputy Prime Minister, John Prescott, who will make the final decision. Details: www.english-heritage.org.uk/stonehenge