M26 motorway the M26 at that time formed part of Ringway 4 and would have been designated as part of the M25. Construction of the first part of the M25 began in 1972 but before it opened, plans for the "London Orbital" motorway were modified to combine the southern and western part of Ringway 4 with the northern and eastern part of Ringway 3. To connect the two separate routes, which together were numbered as the M25, an additional section of road needed to be planned and the M25 route was diverted northwards from junction 5 to meet Ringway 3 at Swanley
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.