From the early 1950s, Brown's arthritic condition (first appearing when she was sixteen) began to make playing on the stage difficult; her mobility was restricted and she was in great pain, which was kept at bay by drugs.

Nevertheless, she was a notable success as Jennet in the London production of Christopher Fry's The Lady's Not For Burning, opposite Richard Burton, Claire Bloom and John Gielgud (1949), which transferred to Broadway for an extended run (1950–51).

[5][6] Time magazine wrote (20 November 1950): "As the lady, Pamela Brown proves that Fry did not write the part for her in vain.

"[7] Brown's success in film continued as Jane Shore in Laurence Olivier's Richard III (1955) and opposite Kirk Douglas in the Van Gogh biopic Lust for Life (1956).

A devout Roman Catholic, she could not remarry while Copley was still alive but chose to live with her partner Michael Powell, the director who had given her early film roles.