The Northern Line is London’s north-south connection and is the busiest line on the network. It was the first using deep boring and first to operate using electric traction.
The southern extension opened in 1926 with seven new stations, all designed by Charles Holden in a modern style. With the exception of Morden and Clapham South, where more land was available, the new stations were built on confined corner sites at main road junctions in already developed areas. Holden made good use of this limited space and designed impressive buildings, with a commanding street presence.
The street-level structures are of white Portland Stone with tall, double-height ticket halls, with the famous London Underground roundel made up in coloured glass panels in large glazed screens. The large expanses of glass ensure that the ticket halls are bright and, lit from within at night, welcoming.
The first and last new stations on the extension, Clapham South and Morden, include a parade of shops and were designed with structures capable of being built above (like many of the earlier Central London stations).