The station can be divided in two parts: underground platforms, opened in 1868 and deep-level platforms, opened in 1913. It is one of two separate Underground stations of the same name. The other station, to the north of the mainline station, is in the Circle and Hammersmith & City lines. Although shown on the London Underground map as a single station, the two stations are not directly linked and exchange between them is via the merge of the mainline station.