Named after Shakespeare’s Cymbeline heroine, she was born in Woking, Surrey, to a family of artists and businessmen. Her grandfather, John Hassall, and her aunt, Joan Hassall, worked as illustrators, while her father, Christopher Hassall, was a poet and lyricist. Her godfather is said to have been the composer Ivor Novello, with whom her father had worked extensively as lyricist. Yet on occasion Imogen would proudly claim that this distinction was Sir William Walton’s with whom her father had collaborated in the early 1950s, quietly denied by Lady Walton.  Imogen boarded and attended Elmhurst Ballet School, Camberley 1952-1954 and the Royal Ballet School, White Lodge, Richmond Park 1955-1958 and continued her absorption of the theatre mode with study at the London Academy of Music and Dramatic Art,1960-1962, following which she joined the company of the Royal Shakespeare Company for one season. After enjoying an appearance in the William Douglas-Home comedy “The Reluctant Peer” at the Duchess Theatre in 1964, she appeared in British TV adventure series of the 1960s such as The Saint, The Avengers, and The Persuaders! In her first significant film role she played Tara in The Long Duel (1967). She gained further public notice as a dominant cave-girl in When Dinosaurs Ruled the Earth (1970) and played major roles in Carry On Loving and the cult horror film Incense for the Damned the same year. In 1974 she appeared in White Cargo (London strippers get kidnapped for Arab sheikh’s harem) alongside David Jason.

Imogen was twice married – firstly to Hawkeye actor Ken Ives (who later married the comedienne Marti Caine) and briefly to Andrew Knox, the actor who appeared in Doctor on the Go and who also committed suicide – and her private life was a regular subject of interest in tabloid newspapers. She was known for playing sexy, scantily-clad characters in film and on TV. This, and the revealing outfits she wore at film premieres resulted in her being publicly referred to as “the Countess of Cleavage”.  She was found dead in her Wimbledon home on the morning of 16 November 1980 when she failed to meet a friend, actress Suzanna Leigh, with whom she was due to go on holiday to Africa that day. She had committed suicide by overdosing on Tuinal tablets.