[citation needed] At age 11, she began performing as a child actress on radio programmes, including the part of Bunkle, an extrovert prep-schoolboy on Children's Hour from Manchester, and later worked as an assistant stage manager and acted with the repertory company at the Prince's Theatre in Bradford during high school.

[3] At the age of sixteen, Whitelaw met the director Joan Littlewood at the BBC in Manchester and was invited to join her Theatre Workshop troupe.

She was encouraged by her mother to join Harry Hanson's Leeds company in 1948 and then went on to play in repertory theatres in Dewsbury, New Brighton in Liverpool and Oxford, eventually making her London debut in 1950.

She starred with Albert Finney in Charlie Bubbles (1967), a performance which won her a BAFTA award as Best Actress in a Supporting Role.

She would win her second BAFTA as the sensuous mother of college student Hayley Mills in the psychological study Twisted Nerve (1969).

She continued in film roles including Leo the Last (1970), Start the Revolution Without Me (1970), Gumshoe (1971) and the Alfred Hitchcock thriller Frenzy (1972).

[citation needed] Whitelaw gained international acclaim for her chilling role as Mrs Baylock, the evil guardian of the demon child Damien in The Omen (1976).

[5] Other films included performing the voice of Aughra in The Dark Crystal, as the hopelessly naive Mrs. Hall in Maurice (1987), one of two sisters, with Joan Plowright, struggling to survive in war-time Liverpool in The Dressmaker (1988), the fiercely domineering and protective mother of psychopathic twin murderers in The Krays (1990), a performance that earned her a BAFTA nomination, as the nurse Grace Poole in Jane Eyre (1996) and the blind laundress in Quills (2000).

Whitelaw became Beckett's muse, as he created, reworked and revised each play while she physically, at times to the point of total exhaustion, acted each movement.