Traffic on the northbound carriageway was stopped near junction 20 for Lutterworth, Leicestershire, due to the collision near junction 21 for Leicester south and the M69 link. Traffic was back to junction 19 - the M6 interchange - near Rugby, Warwickshire.

       Four cars were involved in the smash, Leicestershire Live says.

       East Midlands Ambulance Service and Leicesershire Fire and Rescue crews dashed at the scene.

       At least one lane was closed, it is believed.

       Although traffic was congested, a diversion was not in place.

       National Highways tweeted: The #M1 northbound #J20 (#A4303 #Lutterworth #A4304 #MarketHarborough) to #J21 (#M69 #Coventry #A5460 #Leicester) 1 lane has been closed due to a serious collision.

       "@LeicsFireRescue @EMASNHSTrust Recovery & Traffic Officers are currently at the scene."

       The southbound carriageway was also slow due to onlookers.

       Traffic was back to junction 21a for the A46, Groby, Leicestershire and the western parts of the city.

       It is not yet known if anyone has been injured in the accident.