Under original proposals it would have been greater, taking all of Dulwich and Brixton and possibly two parishes to the east. The commissioners appointed to fix parliamentary boundaries attempted to equalise the seven new "metropolitan" constituencies of London in number of voters and in population. For this reason Bermondsey and Rotherhithe were assigned to Southwark. It was also decided not to include the entirety of the parishes of Camberwell and Lambeth: both were very large parishes running five or six miles south from the Thames. The portions closest to the river were heavily built up, but the southern sections were mainly rural. Dulwich and part of Brixton were therefore excluded, instead forming part of East Surrey.