A serious crash involving a car and a motorcycle in East Devon caused major traffic disruptions in Somerset this evening.
The A303 has been closed in both directions from the A30 junction and the Southfields Roundabout in Ilminster following the collision at Upottery at around 1.40pm this afternoon.
A section of the A30 is also closed between Upottery and Honiton.
Devon and Cornwall Police confirmed that the air ambulance had been called to the scene, and that diversions have been put in place.
The road was not expected to reopen before 7.30pm this evening.
The road closure caused major tailbacks in both directions this afternoon, particularly during rush hour.
In Somerset, queues built up along the A303 back as far as South Petherton, while the A358 from the Southfields Roundabout to the M5 motorway at Taunton was also gridlocked.
In Devon, queues built up with reports of tailbacks to Honiton.
Police advised motorists to avoid the area and seek an alternative route where possible.
Drivers trying to travel westbound are advised to leave the A303 at the A358 and travel south to Chard before taking the A35 west to re-join the A30 at Honiton or Stockland Hill.
Motorists trying to travel eastbound are advised to leave the A30 at Stockland Hill and travel along the A35 towards Chard.