All three lanes of the M4 westbound have now been closed and cars are being turned around at the scene. Flames have erupted from a hay lorry on the M4 (Image: Newsquest)Flames have erupted from a hay lorry on the M4 (Image: Newsquest)A spokesperson for Wiltshire Police said: "Please be aware that the M4 westbound between junctions 15 and 16 is closed due to a significant lorry fire. Flames have erupted from a hay lorry on the M4 (Image: National Highways)A spokesperson for National Highways said: "The M4 has closed westbound between J15 Badbury and J16 Swindon due to an HGV fire. The AA's traffic monitors state: "All lanes stopped and queueing traffic due to vehicle fire on M4 Westbound between J15 A419 Marlborough Road (Swindon East) and J16 A3102 Swindon Road (Swindon West)." Motorists travelling on the M4 westbound past Swindon should avoid the motorway and find alternative routes where possible.