Fremlin studied Classics at Somerville College, University of Oxford.
[1] Her many crime novels and stories helped modernize the sensation novel tradition by introducing criminal and (rarely) supernatural elements into domestic settings.
[1][2] With Jeffrey Barnard, she was co-presenter of a BBC2 documentary, Night and Day, describing diurnal and nocturnal London, broadcast on 23 January 1987.
[3] In 1983 civil proceedings were brought against her as one of the five members of the EXIT Executive committee which had published A Guide to Self Deliverance, but the court refused to declare the booklet unlawful.
[1] Lucy Lethbridge has written of Fremlin's work that "almost all her novels centring round the home as the harbour of a particularly horrible, intimate, terror".