THE M4 has closed in both directions between junctions 14 and 15 after a lorry caught fire.
Firefighters are working at the scene due to a danger of explosion.
Highways England have said that because of the contents of the lorry, it has shut the route completely between Swindon and Membury Services.
It has urged people caught up in the congestion not to leave their vehicle.
Other incidents should be reported via the Highways England Customer Contact Centre on 0300 123 5000.
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