UPDATE: All three lanes reopened at around 4pm
A large number of emergency crews and recovery workers are currently on the scene of the crash southbound between junction 17 near Watford Gap and junction 16 for Northampton.
Northamptonshire Fire and Rescue Service tweeted: "Incident 13:29 Crews from #Daventry #Mereway #TheMounts with assistance from @WarksFireRescue dealing with an RTC involving HGV's on the M1 Junction 17-16 Southbound, 3 lanes are currently closed"
Footage taken by a passenger shows two heavy goods vehicles are involved, one of which has been badly destroyed.
One lane remains open past the crash scene.
Severe delays are being reported on the M1 as a result.
Highways England is advising people to plan ahead if travelling south on the M6 in Warwickshire.