A crash has closed the A1 southbound to the north of Grantham.
Lincolnshire Police have confirmed that the stretch of dual carriageway between the junctions for Marston and Great Gonerby is closed following the crash at just around midday on Wednesday, February 1.
The force has said that the crash involved a black Vauxhall Astra and a blue Ford Fiesta.
A vehicle is believed to have overturned in the collision.
An air ambulance as called to the crash.