National Highways has issued a warning to drivers after the M4 was closed in Wiltshire because of an HGV fire. The motorway was shut by traffic officers between junction 18 at Bath and junction 17 at Chippenham after the large vehicle caught alight, at around 2.15pm on Saturday, July 20.

At the time of writing, the carriageway remains closed westbound heading from Chippenham to Bath with police and fire crews at the scene. The eastbound carriageway was reopened shortly after 3.30pm but there remains long delays.

The AA has reported that smoke has been seen blowing across both carriageways while emergency services work to deal with the situation. In the meantime, National Highways has issued diversion routes for motorists travelling in both directions. There remains severe congestion at both junctions as three lanes of traffic try to exit the motorway at once, and people are warned to reroute or delay their journeys to avoid delays.

READ MORE: Long delays as traffic at a standstill on M4 after incident (Image: National Highways) A spokesperson said: “If this closure impacts on your planned route, please allow extra journey time. “Plan ahead, you may wish to reroute or even delay your journey. “Further information is available from National Highways by visiting our website and travel apps, or via our regional X feed.

“Our 24/7 contact centre team is also available to provide up to the minute information on 0300 123 5000.” The diversion route for those heading westboun.