The Swindon-to-Marlborough road is closed due to a serious head-on collision.
Emergency crews, including Great Western Air Ambulance, have been attending the scene since around 4pm this afternoon. The A346 is closed in both directions.
A vehicle is understood to have attempted an overtake, colliding with an oncoming vehicle.
Four people have been injured, including one who was freed from a car by firefighters.
On the Swindon side, the road is closed at Chiseldon.
The road is likely to be closed for several hours for collision investigation.
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