THE A303 in Somerset is closed in both directions between the junctions with the A356 (South Petherton) and A358 (Ilminster) due to a serious multiple vehicle collision.
All emergency services are working at the scene with a response being led by Avon and Somerset Police.
Highways England say the road will remain closed through the evening.
A Highways England spokesperson said: "Westbound traffic is being diverted via the 'Hollow Triangle' symbol. From South Petherton, take the A356 southbound to Crewkerne, then the A30 westbound to Chard, joining the A358 northbound and continuing to rejoin the A303 at Ilminster.
"Eastbound traffic is being diverted via the 'Solid Circle' symbol, following the reverse of the westbound diversion."
An Avon and Somerset Police spokesperson said: "At about 5.30pm today (Sunday, February 14) we were made aware of a collision on the A303 near South Petherton.
"Police, fire and ambulance services are at the scene.
"The road is shut in both directions and is expected to be shut into tomorrow morning. We'd ask drivers to avoid the area."
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