The M1 in Northamptonshire will remain closed until 10pm tonight between Junction 15a and Junction 18 northbound after an accident, according to the police.
The road was shut at about 2am after an accident involving a lorry and a fuel spillage.
Diversions are in operation through the A43, A5 and A428 to Junction 18. The road remains closed.
The closure has caused huge tailbacks on the M1 and severe delays around the Weedon Bec at the A5 and A45 junction, as well as southbound on the A43 near Towcester and the A5 junction northbound.
Pc Dave Lee, from Northants Police, said the road was not due to reopen until 10pm tonight from Junction 15a northbound to junction 17.