Timeline of the London Underground

Over the next forty years, the early sub-surface lines reached out from the urban centre of the capital into the surrounding rural margins, leading to the development of new commuter suburbs.

At the turn of the nineteenth century, new technology—including electric locomotives and improvements to the tunnelling shield—enabled new companies to construct a series of "tube" lines deeper underground.

Initially rivals, the tube railway companies began to co-operate in advertising and through shared branding, eventually consolidating under the single ownership of the Underground Electric Railways Company of London (UERL), with lines stretching across London.

In 1933, the UK Government amalgamated the UERL and the Metropolitan Railway as a single organisation, named the London Passenger Transport Board.

The London Underground has since passed through a series of administrations, expanding further by the construction of new extensions and through the acquisition of existing main line routes, culminating in its current form as part of Transport for London, the capital's current transport administration, controlled by the Greater London Authority.