During World War II Gardiner volunteered to join the Friends' Ambulance Unit, as an alternative to military service, although he was actually just over conscription age, and served 1943 to 1945; as someone relatively mature, he was usefully able to lead a 55-strong team assisting refugees in the turmoil of North-West Europe in the last year of the war.

[1] He represented The Daily Mirror and its columnist 'Cassandra' (William Connor) in a notable libel trial in 1959 when the pianist Liberace claimed that a newspaper article imputed that he was homosexual.

[7] More successfully, he was the Counsel for the Defence in R v Penguin Books Ltd, the trial for obscenity of the publishers of Lady Chatterley's Lover in 1960.

[10] On the Labour Party's General Election victory in 1964, he was appointed Lord Chancellor and to the Privy Council of the United Kingdom in 1964 by Harold Wilson.

He also alluded to a need to take a ride around the park in his chauffeur-driven car with the Attorney-General to ensure security of their conversations – rather than having 'security' listen in[12] Lord Gardiner published the Minority Report in March 1972 as part of the Parker Report (Report of the Committee of Privy Counsellors appointed to consider authorised procedures for the interrogation of persons suspected of terrorism),[13] which considered the interrogation procedures used against suspects of terrorism in Northern Ireland, with particular reference to allegations of torture during internment in 1971 (See Sensory deprivation, Use of torture since 1948#United Kingdom, Five techniques).

[14] In June 1981 Gardiner survived an assassination attempt when a bomb containing 3 pounds of explosive was attached to his car by the IRA during a visit to Belfast.

The device was later found near the junction of University Road and Elmwood Avenue, Belfast, and defused by the British Army.

The IRA released a statement saying: "We meant to kill Gardiner, the political architect of the criminalization policy and the H-blocks.

[1] In 1970, Gardiner married Muriel Box, a writer, producer and director who had won an Academy Award for Best Original Screenplay for The Seventh Veil.