The London Borough of Bromley was formed on 1st of April 1965, as a result of the London Government Act 1963. It was an amalgamation of the Municipal Boroughs of Bromley and Beckenham together with the Urban Districts of Orpington and Penge and the Chislehurst portion of Chislehurst and Sidcup Urban District Councils (UDCs). The following year there was a minor boundary change when, following an appeal, Knockholt was removed from Bromley and London and returned to Kent.