 During his time in the House of Commons, Cocks served as a Labour whip in government and in opposition, being Chief Whip from 1976–85.Cocks was created a life peer on 6 October 1987, becoming Baron Cocks of Hartcliffe, "of Chinnor in the County of Oxfordshire" and served as vice-chairman of the BBC 1993–98.He also served as Deputy Chairman of the London Docklands Development Corporation.