All emergency services were at the scene of a crash on the A14 this morning.
The collision was between Alconbury and Spittles with the southbound carriageway closed.
Police were asking motorists to avoid the area.
A police spokeswoman said: “We were called at 7.40am this morning with reports of a collision at the junction with the A1M and the A14 at Alconbury involving four vehicles.
“The location is about half a mile before Spittals coming from the A1M.
“The road is completely blocked. It is closed off at the junction to the A14 from the A1M.
“All parties are conscious and breathing. One driver is trapped with serious injuries.