The M1 has re-opened north of Milton Keynes following a 'serious collision' involving two lorries.
Police closed the southbound carriageway between J18 at Daventry and J17 for the M45 in Northamptonshire for a number of hours earlier.
The northbound carriageway was also moving very slowly past the scene.
Northamptonshire Police, Fire & Rescue and East Midlands Ambulance Service attended the scene along with Highways England Traffic Officers.
An air ambulance also landed at the scene.
Queues were back to J19 for the M6 with long delays in the area.
Traffic has now returned to normal.
