Highways England tweeted at about 2.40pm: "#M1 northbound between J16 and J17, by Watford Gap services is currently blocked due to a car fire. #TrafficOfficers are on scene and emergency services are attending. Please look for alternate routes if heading north. This will cause considerable delays."
UPDATE: Just before 5pm Highways tweeted: "All lanes are now open following a car fire.
"Congestion is heavy between J15 to J17 so please plan ahead and allow additional time, or look to use alternate routes if driving north over the next hour or two"