The A303 is a trunk road in England. The A303 is the main road between Basingstoke in Hampshire and Honiton in Devon. The M3, A30 and A303 make up the main route from London to South West England, running from London to Land's End in Cornwall. The A303 is almost continuously dual carrageway, except at Stonehenge and Chicklade in Wiltshire, and the Black Down hills in Somerset. The Minister for Transport announced major road widening schemes in 2003.

On June 5 12.5km of improvements, including a new 2.1km bored dual carrageway Tunnel under stonehenge were announced. On September 4 a public enquiry into whether the plans are adequate was announced. Chicklade is to gain a bypass, and the road will be widened through the Black Down hills. Work is scheduled to be completed in 2008