An overturned van blocking several lanes has wreaked havoc on the M1 this morning.
There were two casualties after the vehicle collided with the hard shoulder.
It is unclear how the accident happened and Herts police are examining the incident.
All but one lane southbound, towards St Albans and between junctions eight and nine, was closed and traffic has been passing the incident on the hard shoulder.
It happened at about 3am, but the motorway is not expected to clear until after the morning rush hour.
Herts police, three firefighting crews from the Herts Fire and Rescue Service, and the East of England Ambulance Service were all on the scene to recover the vehicle and care for two casualties.
Highways England estimate delays to be around two hours stretching back to junction 11.
For more information, visit www.trafficengland.com/
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