Three lanes on the M1 southbound have been closed this afternoon after a crash.
Long delays of up to an hour have been reported by AA Traffic News between junction 14 for the A509 (Milton Keynes) and junction 15 for the A45 (Northampton).
Highways East Midlands has said traffic is currently at a standstill while emergency services deal with the collision and have 'no current ETA' for when they can release traffic.
Diversions have been put in place and road users are advised to follow the 'Hollow Circle' diversion symbol and exit the M1 at J15 onto the A508.
Continue on the A508 through Roade and Grafton Regis to the A508/A5/A422 Old Startford Roundabout.
At the roundabout take the first exit onto the A5. Continue along the A5 until the A5/A509 Portway. Take first exit onto the A509 Portway, then re-join the M1 southbound at J14.
Wider strategic traffic heading for London and South East destinations are encouraged to use the M40 route from the Midlands.
Road users are advised to allow extra time for their journeys and consider alternative routes.