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
M25 motorway M25 motorway The M25 or London Orbital Motorway is long encircling almost all of Greater London, England (with the exception of North Ockendon). An ambitious concept to build four concentric ring roads around London was first mooted in the 1960s. A few sections of the outer two rings were constructed in the early 1970s, but the plan was abandoned and the sections were later integrated to form a single ring which became the M25, aka London Ring Road, finally completed in 1986. It is one of the busiest of the British motorway network: the stretch between Junctions 14 and 15