Hennessy was elected to
Westminster Borough Council in 1958 to 1962, unsuccessfully contested
Tottenham in
1959, and entered the
House of Lords as the 3rd
Baron Windlesham upon his father's death in 1962, who died in a helicopter accident at sea, having been a brigadier in the Grenadier Guards. He joined the Government as Minister of State in the
Home Office in 1970 to 1972; and from 1972 to 1973, in the
Northern Ireland Office, after which he became
Lord Keeper of the Privy Seal and
Leader of the House of Lords in June 1973 until October 1974. On 16 November 1999, he was created
Baron Hennessy, of Windlesham in the County of Surrey after the
House of Lords Act 1999, so that he could continue sitting in the Lords. ==Media==