The M4 motorway is currently closed westbound between junction 15 for Badbury and junction 16 for Swindon due to a significant fire. A lorry carrying bales of hay is involved, with 10 to 15 tonnes of hay bales still alight and charred.
Dorset and Wiltshire Fire and Rescue Service crews are at the scene. No injuries have been reported.
Wiltshire Police expect the westbound carriageway to remain closed until late afternoon. Potential emergency repairs to the road could lead to some overnight closures.
National Highways and Wiltshire Police are releasing trapped traffic. Westbound traffic is being diverted from junction 15 along local roads to rejoin the M4 at junction 16.