[3] Hyson made her acting debut at age three, playing her mother's daughter in a silent film shot by director George Fitzmaurice at New York's Paramount studios.

Filming at Blackpool with Gracie Fields Sing As We Go and acting in the West End in Dodie Smith's Touch Wood led to a nervous breakdown.

During the Second World War, Hyson made several more films including You Will Remember with Robert Morley and the musical comedy Spare a Copper with George Formby.

She also acted in revue, musical comedy and plays like the thriller Pink String and Sealing Wax in 1943 and an adaptation from Trollope Scandal at Barchester in 1944.

[3] She worked at the secret codebreaking establishment Bletchley Park during World War II,[5] She was part of a team of twelve led by Patricia Bartley who broke the German diplomatic code, Floradora.