text: The carriageway was closed between junction 15 near Northampton and Newport Pagnell Services, with congestion stretching back as far as junction 15a for Towcester.
  Police were called to the incident at about 18:45 BST on Thursday and have also closed two northbound lanes.
  A Northamptonshire Police spokesman said traffic was being turned around in an attempt to get it off the motorway.
target: A lorry fire has closed a southbound section of the M1 in Northamptonshire.