 In the 1920s, as part of the construction of what is now the Northern line, the CCE & HR was extended south to Waterloo and Kennington where it was connected to the City & South London Railway. The loop tunnel under the river was abandoned (although the present northbound Northern line platform follows its course) and two new tunnels were bored south. To this day the southbound Northern line platform is the only one of the four deep level platforms that is not connected to any of the others by deep level walkways. The new extension was opened on 13 September 1926.
