The entire southbound stretch of the M1 between Northampton and Milton Keynes remains closed this afternoon.
Emergency services were forced to close the M1 following a serious crash between a van and a lorry at around 10am this morning (Wednesday).
It is not expected to open until around 5.30pm today. Highways England has apologised for the inconvenience.
Officers from Highways England have been working for several hours to release stranded motorists caught within the closure.
At 3pm @HighwaysEMIDS tweeted: "All trapped traffic has now been released past the scene.
"For those that were stuck thank you for your understanding and patience. Safe onward journeys."
If you are diverting off at junction 15 please use the A508 and A5 which will divert you back on to the M1 at J14.
All other routes advised are to use the A42 at J23A and then the M40.