Emergency services are dealing with a crash involving four vehicles on the A1 north of Grantham.
The crash was reported just after 11am on the northbound carriageway near to the Long Bennington slip road and involved a Renault articulated lorry, a Ford box van, a red Volvo lorry and a Silver Mercedes Benz.
The air ambulance was called after one person was reported injured in the accident.
At least four fire crews have headed to the scene.
Police say diversions are in place but expect delays.
UPDATE: The road has now been re-opened (12.30pm) but traffic is moving slowly.