Drivers are being warned that the M1 southbound is closed in Northamptonshire after an accident involving a minibus and two LGVs.
All three lanes are closed between junction 15 (Northampton East) and junction 14 (Milton Keynes.)
Thames Valley Police and the fire service are continuing to work at the scene and the carriageway is likely to remain closed for several hours.
Highways England has set diversion routes from junction 15, with traffic following the A508, A5 and A509 to rejoin the M1 at junction 14. Drivers are being advised to consider alternative routes, including the M40.
Two lorry drivers are to stand trial over a horror crash on the M1 that left eight people dead.
A lorry driver accused of causing the deaths of eight people in a crash on the M1 in Buckinghamshire has appeared in court.
Two men have been charged with causing death by dangerous driving after a crash on the M1 near Newport Pagnell.