A business leader is urging the Government to give the economy a boost by reviving plans to build a tunnel underneath Stonehenge.

John Cridland, director general of the CBI, said reducing congestion on the busy A303 was ''vital'', despite the difficulty of bypassing the World Heritage Site in Wiltshire.

''The most significant barrier is Stonehenge. You obviously can't move it, so why not go under it?'' he said.

Similar proposals were dropped seven years ago on cost grounds, but plans are being discussed by a working group that has been looking at ways to reduce congestion on the A303 since the spring.

An announcement about upgrading the whole A303 - which runs from Honiton in Devon to Basingstoke, Hampshire - is expected in the Chancellor's Autumn Statement next month.

A new visitor centre has been built at Stonehenge and an adjacent road closed, but the area remains blighted by massive traffic jams.