From the Wikipedia page [1] Middlesex County Council was the principal local government body in the administrative county of Middlesex from 1889 to 1965. The county council was created by the Local Government Act 1888, which also removed the most populous part of the county to constitute the County of London. By the 1930s most of the county had become urbanised, effectively forming part of the London conurbation, and in 1965 the county council was abolished on the creation of the Greater London Council.