The UERL's three deep-level tube railways that were merged into the London Electric Railway
The London Electric Railway (LER) was an underground railway company operating three lines on the London Underground. It was formed in 1910 and existed until 1933, when it was merged into the London Passenger Transport Board.
An Act to amalgamate the Baker Street and Waterloo Railway Company and the Charing Cross Euston and Hampstead Railway Company with the Great Northern Piccadilly and Brompton Railway Company and to confer further powers on the Great Northern Piccadilly and Brompton Railway Company and for other purposes.
Although the LER management was combined, the three lines continued to be identified separately for operational purposes as the Bakerloo tube, Hampstead tube and Piccadilly tube.
^Horne, Mike (2009). The Northern Line: An Illustrated History (3rd ed.). London: Capital Transport Publishing. p. 28. ISBN978-1-85414-326-6.
^Wolmar, Christian (2005) [2004]. The Subterranean Railway: How the London Underground Was Built and How It Changed the City Forever. Atlantic Books. p. 266. ISBN1-84354-023-1.