At the time a forensic team could be seen erecting a tent around cars, some spun completely around by the collision. A logistics lorry was seen parked on the hard shoulder.
National Highways confirmed at 6.30am that the accident had been cleared after crash investigations by the Met Police were completed.
A spokesman said: “There’s still a 60 minute delay in the area with 4 miles of congestion, so please allow extra journey time this morning.”
Drivers reported on social media being stuck in traffic for as long as eight hours before being directed to turn around about 3am.
Scotland Yard has been approached for comment.