The Piccadilly line was originally called the Great Northern, Piccadilly and Brompton Railway.
The railway opened in 1906 between Hammersmith and Finsbury Park. Its long original name reflected the companies and routes involved in creating the line. It became part of the Underground network administered by the London Passenger Transport Board in 1933 and was subsequently known simply as the Piccadilly line.
The line is shown in dark blue on the Tube map. It later expanded to serve destinations including Heathrow Airport, Uxbridge and Cockfosters. Its central section passes important locations such as Leicester Square, Piccadilly Circus and King’s Cross St Pancras.
The name is sometimes confused with the Great Northern Railway, which was a separate main-line railway company. The Piccadilly line’s original title referred specifically to the Great Northern, Piccadilly and Brompton Railway, not to the entire Great Northern main-line system.