The A303 in Wiltshire is closed in both directions following a major lorry fire.
The fire broke out around 5am while the lorry passed between the junctions for the A350 (Higher Pertwood) and the A36 (Deptford).
Pictures on social media showed the scorched remains of the lorry and its contents at the side of the carriageway.
The fire has been extinguished but Highways England says the clean-up operation, which is currently underway, is likely to take several hours.
Motorists are being diverted via the A36 through Heytesbury towards Warminster and the A350 through Longbridge Deverill before being allowed to rejoin the A303.