Fielding was born in Ootacamund, India, where his father, Alexander James Lumsden Wallace, served in the Indian Army, as a major in the 52nd Sikhs (Frontier Force).

[citation needed] Following the fall of France, Fielding joined the British Army,[3] and was commissioned into the Cyprus Regiment as a second lieutenant on 1 September 1940.

[3] Fielding teamed up with Patrick Leigh Fermor, and built an intelligence gathering network which provided detailed information on the movement of Axis troops, shipping, and air transport.

[3][8] In November 1943 he successfully concluded a pact between the two rival groups of andartes, the communist-led EAM-ELAS and the EOK, the national organisation of Crete.

[3] On 13 August 1944, two days before the Allied landings in southern France, Fielding, Cammaerts and French agent Christian Sorensen were stopped at a roadblock near Digne.

[3] He wrote a number of books; including The Stronghold, an account of SOE's Cretan operations, and a memoir of his own wartime experiences Hide and Seek (which he dedicated to Christine Granville).

Fielding also collaborated with Patrick Leigh Fermor in a translation from Greek of George Psychoundakis' book The Cretan Runner His marriage to Lady Daphne was dissolved in 1978.