A loaded car transporter has caught fire on the M4 in Wiltshire between Swindon and Chippenham.
The motorway is currently closed westbound between junction 16 and 17.
Emergency services are at the scene.
Drivers have been advised to allow extra time for their journey and follow the diversion signs in place.
HGVs are being diverted via junction 15 while all other traffic is being diverted off junction 16 via local roads.
The eastbound carriageway was also blocked earlier today due to thick smoke, it has since reopened.