An overturned car caused major delays on the M40 between junctions 10 at Brackley and junction 11 at Banbury.
Traffic is heavy but moving on both sides of the carriageway.
A diversion had been placed into operation taking traffic via the A43 north to Brackley, the A422 west to Banbury and then to rejoin the M40 at junction 11 but now all lanes of the motorway have re-opened.
Congestion remains on the M40 up to J9, A34 Bicester.
Fuel leaking from the overturned vehicle is slowed down the recovery efforts.