The M4 has been closed in Wiltshire this morning after a crash involving six vehicles, after a horse ran onto the road.
Traffic on roads to Swindon, Oxford, Cirencester and the Marlborough Downs is also suffering major delays.
The horse, one of three which escaped from a field on the Wiltshire/Berkshire border, was hit by a van, which overturned, trapping a man inside.
It is thought five other vehicles are also involved in the crash, which has closed the motorway eastbound between junctions 15 and 14, and caused tailbacks to junction 16.
The eastbound A303 in Devon is also closed between the Marsh turn junction and the Giant's Grave junction, because of an accident involving two vehicles. Slow traffic eastbound between the A30 junction in Upottery and Southfields Roundabout in Donyatt.
And the A361 at Burrowbridge on the Somerset Levels remains closed. Diversions in place.