Chislehurst and Sidcup Urban District

From the Wikipedia page

Chislehurst and Sidcup Urban District was a local government district and civil parish in north west Kent, England from 1934 to 1965.

It was formed in 1934 from the former area of Chislehurst Urban District, Sidcup Urban District and part of Bromley Rural District.

In 1965 the parish and urban district were abolished and the settlements split again so Chislehurst became part of the London Borough of Bromley while Sidcup and North Cray formed part of the London Borough of Bexley in Greater London.