Traffic is building up following a collision on a busy motorway. Motorists are facing long delays after Dartford Tunnel was closed for an hour following an accident between junction 1 for Dartford and junction 31 for Lakeside just after 7am. Traffic is queuing back to Gravesend on the A2 and junction 3 at Swanley on the M25 as well as one mile either side on the A206 at junction1a. All lanes have now reopened. Listen to kmfm for travel updates. Drivers are advised to leave extra time for their journey.