Three people, including two police officers, have been injured in a crash on the A52 which has caused the road to close.
The crash happened just after 10am on Wednesday morning and will see the A52 closed in both directions at the Mareham Lane junction near Threekingham until around 5.30pm.
Two police officers and the driver of the other car suffered minor injuries and have been taken to hospital for treatment.
It happened when the police car was responding to an emergency call, and investigations are taking place to find out what happened.
Anyone who was in the area or has dashcam footage is being asked to call 101 and quote incident 111 of June 16.