M25 motorway re-examined as a motorway route in Sir Charles Bressey's and Sir Edwin Lutyens' "The Highway Development Survey, 1937". Sir Patrick Abercrombie's "County of London Plan, 1943" and "Greater London Plan, 1944" proposed a series of five roads encircling the capital. The northern sections of the M25 follow a similar route to the World War II Outer London Defence Ring, a concentric series of tanks and pillboxes designed to slow down a potential German invasion of the capital. Little was done to progress these plans until the 1960s when the Greater London Council developed its London Ringways plan consisting of four
M60 motorway unsigned Euroroutes E20 and E22. In 2008, the M60 was proposed as a cordon for congestion charging in Greater Manchester, although this was rejected in a referendum relating to the Greater Manchester Transport Innovation Fund. The M60 is the only true orbital motorway in the United Kingdom; the M25 motorway in London is not, due to the Dartford Crossing being designated the A282. The M60 was developed by connecting and consolidating the existing motorway sections of the M63, M62, and an extended M66. It came into existence as the M60 in 2000, with the completion of the eastern side (Junctions