Officers were called at around 10-10pm to reports of a man, aged in his 20s, being on the carriageway on the westbound side of the motorway, close to junction 10.
It is believed he fell from a bridge onto the road and was then struck by passing vehicles.
Despite the best efforts of emergency services he was pronounced dead at the scene. His next of kin have been informed and are being supported by specially trained officers at this distressing time.
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A full closure of the motorway was put in place close to the scene while investigation work was carried out, and the road was reopened at around 6-30am.
Police are now appealing for witnesses to the incident who have not yet spoken to officers, and in particular would like to trace the driver of a car who they believe collided with the man but failed to stop at the scene.
The car is described as possibly being a BMW 1 series.
Sgt Craig Booth, of the Lancashire Police TacOps Unit, said: “First and foremost are thoughts are very much with the family and friends of the man who died. We offer them our sincerest condolences at this incredibly difficult time.
“An investigation is now underway to establish exactly what occurred and we are appealing to anybody who witnessed the collision, and has not yet spoken to officers, to come forward.
“In particular we would like to speak to the driver of a car which we believe may have been involved in the collision but failed to stop at the scene. If this is you, or you think you know who it may be, we would urge you to get in touch with us as soon as possible.”
Anybody with information is asked to get in touch in 101, quoting log number 1371 of December 15th.