Ruislip was a district in the north-west of London.
Roughly to the north-west of Ruislip were both Amersham and Chesham. Roughly to the north-east was Harrow. (TV: Revenge of the Slitheen)
In the 2000s, the London branch of Coldfire Construction, which was secretly operated by the Slitheen, built a technology block in a Ruislip school, using it as a transducer to absorb energy from the Sun and destroy the Earth so they could sell it off. After Sarah Jane Smith foiled the Slitheen at Park Vale Comprehensive School, Ealing, she called UNIT so they would clear up the Coldfire sites across the world. (TV: Revenge of the Slitheen)