M25 motorway the east of Gravesend and Grays, the Lower Thames Crossing, in order to relieve congestion on the A282 Dartford Crossing and connect the M25 at North Ockendon in Essex with the M2 in Kent. At Junction 5, the clockwise carriageway of the M25 is routed off the main north–south dual carriageway onto the main east–west dual carriageway with the main north–south carriageway becoming the A21. In the opposite direction, to the east of the point where the M25 diverges from the main east–west carriageway, that carriageway become the M26 motorway. The radial distance from London (taken as Charing Cross) varies
M25 motorway unofficial, and illegal, motor racing. At the end of the 1980s, before the advent of speed enforcement devices, owners of supercars would meet at night at service stations such as South Mimms and conduct time trials. Times below 1 hour were achieved - an average speed of over 117 mph (188 km/h), which included coming to a halt at the Dartford Tunnel road user charge payment booths. Data from driver location signs provide carriageway identifier information. The numbers on the signs are kilometres from a point near the River Thames, east of London, when travelling clockwise on the motorway. The