Daughter of the television writer Pat Dunlop she began as a child actress in the seventies featuring in a BBC version of the classic A Little Princess and as Lydia Holly in the ITV adaptation of South Riding.
Her transition to adult roles, compared to many, was relatively easy and she received excellent reviews as Lizzie Hexham in a celebrated BBC version of Dickens' Our Mutual Friend (1976) and starred in the very first series of the long-running hospital drama Angels (1975).
She was cast alongside Diana Rigg and Elizabeth Taylor in the film version of Stephen Sondheim's A Little Night Music (1977) and appeared in Roman Polanski's Tess (1979). In 1980 she played Nora, the nurse who is at first terrified by The Elephant Man and then befriends John Hurt's character in David Lynch's 1980 Oscar winning film.
Throughout this time and indeed throughout her career she has regularly appeared on British TV including two guest appearances in Doctor Who, Frontios in 1984 and The Happiness Patrol in 1988. In the 1990s she starred in the long running BBC sitcom May to December as Zoe Callender alongside screen husband Anton Rodgers.
In 1995, she starred in the two part Gurinder Chadha directed drama Rich Deceiver as Ellie Freeman, a Liverpudlian housewife who secretly wins the pools and uses the money to covertly help her husband's career. She also starred in the much underrated ITV series Wokenwell (1997) and appeared in a long-running series of TV commercials for Kleenex directed by Mike Leigh.
In 2000, Lesley joined the cast of the successful ITV series Where the Heart Is playing Anna Kirkwall a typical Dunlop character: Northern (though Dunlop herself is a Londoner), working-class and dependable. As an actress Dunlop has perfected the not inconsiderable task of playing a certain type of British 'Everywoman' with whom an audience easily identifies.
She is currently playing Brenda Walker in Emmerdale (6/4/08)