The M6 between junction 44 and 43 closed in both directions for several hours after a crash involving a police car.
Cumbria Police say the collision happened shortly after 2pm on the southbound carriageway, near Carlisle.
Police, fire crews, and the North West Ambulance Service are all on the scene.
The northbound carriageway is now open to vehicles, but the closure is still in place on the southbound.
Drivers travelling on the motorway are being urged to find alternative routes.
No further information has been released on this incident.
More on this as we get it.