The World's Oldest Underground System

The London Underground is an underground railway system - also known as a rapid transit system (Tube). London is served by 12 Tube lines. It is the world's oldest underground system. The Underground has 275 stations and runs over 253 miles (408 km) of line.

Since 2003, the Underground has been part of Transport for London (TfL), which also administers numerous other transport-related functions, including the famous red double-decker buses.

In the early 20th century, the presence of six independent operators running different Underground lines caused passengers substantial inconvenience; in many places passengers had to walk some distance above ground to change between lines. In 1933 the Combine and all the municipal and independent bus and tram undertakings were merged into the London Passenger Transport Board (LPTB), a public corporation that approximated in scope to the present-day TfL.

During the 1930s and 1940s, several sections of main-line railway were converted into (surface) lines of the Underground. The first real investment came with the carefully planned Victoria line on a diagonal northeast-southwest alignment beneath central London, which opened in stages between 1968 and 1971. The Piccadilly line was extended to Heathrow Airport in 1977, and the Jubilee line was opened in 1979, taking over part of the Bakerloo line, with new tunnels between Baker Street and Charing Cross. In 1999 the Jubilee was extended to Stratford in London's East End, including the completely refurbished interchange station at Westminster, in several stages.

Since January 2003 the Underground has been operated as a Public–Private Partnership (PPP), where the infrastructure and rolling stock are maintained by two private companies (Metronet and Tube Lines) under 30-year contracts, but it remains publicly owned and operated, by TfL.n