The A419 is closed southbound in Swindon due to a broken down vehicle.
Police say that both lanes of the carriageway near Junction 15 of the M4 are shut due to the incident this afternoon (Thursday).
Closures are understood to be in place at both White Hart Roundabout and Commonhead Roundabout to prevent motorists from joining the traffic jam.
There are significant delays, with Google showing standstill traffic on the major route and at connecting junctions.
The road will remain closed for approximately two hours, Wiltshire Police said – though it’s not clear why a break down has resulted in the carriageway being shut.
In a statement, a force spokesman said: “Please be aware that closures are in place on both lanes of the A419 southbound due to a broken down vehicle.
“Drivers are advised to seek alternative routes and expect delays in the area.
“The southbound route near J15 is likely to be closed for about two hours. Thank you for your patience.”
