Southwark was a town in London.
Richard Lazarus was from Southwark, during The Blitz, he hid in the crypts of the Southwark Cathedral. (DW: The Lazarus Experiment)
In 2007, Southwark was at the forefront in the brief Battle of Canary Wharf between the Cybermen and Daleks. Many casualties and damage occured across the streets of Southwark. DWBIT: Doctor Who: Battles in Time Daleks vs Cybermen Special)
Lazarus presented his rejuvination device in Southwark, he was then mutated into a monster that killed several people, he was defeated by the Doctor in the Cathedral. (DW: The Lazarus Experiment)