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 are in Buckinghamshire, 17–25 are in Hertfordshire, and 26–31 are in Essex. Policing of the road is carried out by an integrated policing group made up of the Metropolitan, Thames Valley, Essex, Kent, Hertfordshire and Surrey forces. The M25 is one of Europe's busiest motorways. In 2003, a maximum of 196,000 vehicles a day were recorded on the motorway just south of London Heathrow Airport between junctions 13 and 14. The idea of an orbital road around London was first proposed early in the 20th century. An outer orbital road around London had first been proposed in 1913, and was