A1 closed after a man dies following a collision
The A1 is shut in both directions following a fatal crash.
Cambridgeshire Constabulary was called to reports of concern for a person walking along the central reservation near RAF Wittering, just after 00:00 BST.
Shortly afterwards, a 27-year-old man was struck by a vehicle and died at the scene, the force said.
The road has been closed between the A47 (Wansford) and the B1081 (Wothorpe) and is expected to remain closed for several hours.