She was at her busiest in the late 1950s (Blood of the Vampire) and 1960s when she became Hammer Horror's No. 1 female star, with The Gorgon (1964), Dracula, Prince of Darkness (1966), Rasputin, the Mad Monk (1966), and Quatermass and the Pit (1967) among her credits. She also appeared in Village of the Damned (1960). Although she is known as a scream queen, her most famous scream (in the aforementioned Dracula film) was dubbed by co-star Suzan Farmer.
Her television appearances include the very first Danger Man episode, 'View From A Villa' (1960), plus a subsequent episode that season, 'The Traitor' (also 1960); The Saint (TV series) (1962), two episodes of 12 O'Clock High (1965 and 1966); The Avengers episodes 'Dragonsfield' (1961) and 'From Venus With Love' (1967); the TV miniseries Prince Regent (1979); The Borgias (1981); the Blake's 7 episode 'Stardrive' (1981); and the Doctor Who serial Planet of Fire (1984).
In 2010, Writer and actor Mark Gatiss interviewed Shelley about her career at Hammer Films for his BBC documentary series A History of Horror.