There are seven miles of delays on the M1 after a crash.
Highways England has said that there is currently 45 minute delays between J21a and J21.
One lane is closed and an extra lanes has been opened.
A Highways spokesman said: "There are 45 minute delays on the approach to this M1 collision spanning approx. 7 miles back to J22."
UPDATE: "Traffic has returned to normal now, all lanes open."