The A47 between Guyhirn roundabout and Begdale roundabout is to remain closed in both directions for at least three hours due to a serious crash between a lorry and a van.
An air ambulance, fire crew and police team are on the scene after a van left the road and ended up in a ditch following the crash.
The incident happened at 12.40pm and is causing major traffic delays.
Police have advised drivers to “find alternative routes”, however the road is expected to be cleared between 3.30pm and 3.45pm.
One person said on social media: “Hubby was two cars behind it and caught up in it.
“One of the drivers was having to be cut out. Hopefully they will be okay.”
Several bus routes including the X11 and X12 have been affected by the collision.
Cambridgeshire Police are currently on the scene.
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