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
Safety on the London Underground train. Several stations on the Jubilee line extension are fitted with platform edge doors, which prevent people from falling or jumping onto the tracks. Terrorism in the London Underground has been a major concern because the Underground's importance makes it a prime target for attacks. Many warnings and several attacks, some successful, have been made on the Underground, the most recent on 21 July 2005, although in that case only the detonators exploded. The most recent attack causing damage was on 15 September 2017, when a man detonated a homemade bomb on a District line train at Parsons Green station.