Two people were taken to hospital after a collision between an HGV and a van that has closed the A47 between Wisbech and Guyhirn.
Highways officials are recommending diversions during the busy morning commuter rush whilst investigations continue.
Cambs fire and rescue said two casualties were taken to hospital following the crash that happened just before midnight.
“Two crews from March were called at 11.55pm and released one casualty, another was already out,” said a fire service spokesman.
“Both were taken to hospital by ambulance”
Drivers have been warned the road will remain closed until later this morning.
The recommended diversion will take motorists out on the A141 towards Chatteris and then to Ely before picking up the A10 to head north towards King’s Lynn.
Those travelling in the opposite direction are being urged to head along the A1101 to Outwell, out to the A10 and onto Ely before heading back through Chatteris and along the A141 to Ring’s End.
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