Drivers have been warned of major disruption after a police incident shut the M6 near Wigan earlier.
National Highways said an air ambulance had landed on the motorway and traffic gad been stopped southbound between Junction 27 for Standish, and Junction 26 for Orrell.
The agency said delays of up to an hour were expected, although the road has since reopened.
Traffic has built up towards Charnock Richard service station, located between Junction 28 for Leyland and Junction 27.