Howell was born in London but spent her early years in Somerset, living with her mother and paternal grandparents in a hamlet in the Mendips.
She was artistic director of the Northcott Theatre at Exeter University from 1971 to 1974, where she directed the world premiere of Edward Bond's Bingo in 1973, starring Bob Peck.
Subsequently, Howell and John Dove directed the London premiere of Bingo at the Royal Court Theatre; the cast included John Gielgud, Arthur Lowe, Ewan Hooper, Oliver Cotton, and Paul Jesson.
[2] Among her other work, she directed Edward Bond's Narrow Road to the Deep North in 1968 at the Belgrade Theatre, Coventry, David Mercer's Cousin Vladimir, in 1978 at the Aldwych Theatre, London for the Royal Shakespeare Company, and a 1989 production of Shakespeare's Coriolanus for the Young Vic Theatre, London.
Mini-series she directed include Drums Along Balmoral Drive (1986), Amongst Barbarians (1990) -- both for the series Screenplay—and Into the Fire (1996).