A truck fully laden with chewing gum has crashed across the central reservation of the M40 in Oxfordshire.
The motorway has been closed in both directions after the HGV rolled over and spilt diesel across all the lanes of the southbound carriageway shortly before 05:45 GMT.
The lorry overturned between junctions 8a (Oxford) and 9 (Bicester). Diversions are in place.
Thames Valley Police said it would be a “protracted recovery”.
Highways England said there were long delays, with about four miles [6.4km] of congestion approaching junction 9.
It said the closure was expected to be in place for “several hours for recovery and clear-up work”.