The M25 or London Orbital Motorway is a 117-mile (188 km) motorway that encircles almost all of Greater London, England (with the exception of North Ockendon), in the United Kingdom. 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, completed in 1986.
It is one of the busiest of the British motorway network: 196,000 vehicles were recorded on a busy day near Heathrow Airport in 2003 and the western half experienced an average daily flow of 147,000 vehicles in 2007. To alleviate congestion, sections of the motorway have been widened from the original three-lane carriageways to four-, five- or six-lane carriageways. Other sections use Smart motorway operation with hard shoulders replaced with standard lanes.
The M25, plus the short non-motorway A282 which joins the two ends of the M25 across the River Thames using the Dartford Crossing, is Europe's second longest orbital road after the Berliner Ring, which is 122 miles (196 km).
From the mid 1840s until 1857, Barlow was chief engineer for the Midland Railway, after which he set up his on consultancy in London. Between 1862 and 1869 he was the consultant engineer on the Midland Railway's extension from Bedford to London, designing St Pancras station and the 240-foot (73 m) wide cast iron and glass train shed roof over the platforms, the widest unsupported arch in the world at the time.
Image 22The multi-level junction between the M23 and M25 motorways near Merstham in Surrey. The M23 passes over the M25 with bridges carrying interchange slip roads for the two motorways in between.
Image 23Sailing ships at West India Docks on the Isle of Dogs in 1810. The docks opened in 1802 and closed in 1980 and have since been redeveloped as the Canary Wharf development.
Image 30Arguably the best-preserved disused station building in London, this is the former Alexandra Palace station on the GNR Highgate branch (closed in 1954). It is now in use as a community centre (CUFOS).
Image 37The newly constructed junction of the Westway (A40) and the West Cross Route (A3220) at White City, circa 1970. Continuation of the West Cross Route northwards under the roundabout was cancelled leaving two short unused stubs for the slip roads that would have been provided for traffic joining or leaving the northern section.
Image 38London Underground A60 Stock (left) and 1938 Stock (right) trains showing the difference in the sizes of the two types of rolling stock operated on the system. A60 stock trains operated on the surface and sub-surface sections of the Metropolitan line from 1961 to 2012 and 1938 Stock operated on various deep level tube lines from 1938 to 1988.