 The expansion of the Metropolitan Railway in the early 20th century acted as a catalyst for development in the area . A station was opened in Ruislip in 1904 and the parish council created a new urban district to address the forthcoming population growth . The Ruislip @-@ Northwood Urban District continued until 1965 when Ruislip became part of the newly established London Borough of Hillingdon . Between 1911 and 1961 , Ruislip @-@ Northwood experienced a significant rise in population , from 6 @,@ 217 to 72 @,@ 791 , largely attributed to the extension of the railway . 
