The daughter of Alex Bloom and his wife Goldie at 6 Blairderry Road.The family had been in the business of showing films right from the days of silent cinema. Leaving school at sixteen, she trained to be a secretary, while her father gave her the experience of working in the film business by letting her programme one of his cinemas, The Royal in Deal, Kent, part of the Bloom Theatre Circuit.When her father died in 1968, she inherited his share of the business.
Many of the family's cinemas were low-rent houses in poor condition, so in 1970 Hart took the run-down Rex in Islington, north London, which dates from 1913, and transformed it into an attractive arthouse cinema with a policy of showing films that other exhibitors would not touch. Thus was born the first of her seven Screen cinemas, The Screen on the Green.Hart was also active in other areas of the cinema industry. She became a member of David Puttnam's National Film Finance Corporation board and also served on the admissions board of the National Film and Television School. For her contribution to the film industry she was awarded an OBE in 1993.