Haydn is a four-time Olivier nominee for The Threepenny Opera (NT), Women on the Verge of a Nervous Breakdown (West End), the original London production of City of Angels, and also for her role as the dance teacher in Billy Elliot the Musical (West End and Broadway) for which she won Drama Desk, Outer Critics Circle, Theatre World and Broadway World Awards as well as a Tony nomination.

Other theatre credits include: Anything Goes (Barbican); Copenhagen (Bath Theatre Royal); The Welkin (National Theatre); Hedda in Hedda Tesman (Headlong/CFT); Lady Wishfort in The Way of the World (Donmar Warehouse) and Volumnia in Coriolanus for the RSC. Desirée in A Little Night Music (Huntington Theatre Boston); Margaret Thatcher in The Audience (West End – WhatsOnStage Award for Best Supporting Actress); Richard III (Old Vic/BAM New York); Joanne in Company (Donmar Concerts); Becky Shaw (Almeida); The Memory of Water (Hampstead); The Merry Wives of Windsor, Peer Gynt, Twelfth Night and A Midsummer Night’s Dream (RSC), Hedda in Hedda Gabler (Bolton Octagon) & The Recruiting Officer (Royal Exchange Manchester). Last year she also appeared in Old Friends (Sondheim Theatre), an all-star gala tribute to Stephen Sondheim staged by Cameron Mackintosh, which was screened by the BBC over Christmas.

Television credits include: Camilla in The Windsors, The Crown, The Suspect, Maternal, The Canterville Ghost, The Midnight Gang, Urban Myths: The Trial of Joan Collins, The C-Word, Ripper Street, Sherlock, Rome, Lewis, Midsomer Murders, Poirot, Father Brown, Silent Witness, The Secret and Nice Work. She won Royal Television Society Awards for Dalziel and Pascoe, Peak Practice and Mersey Beat, and was BAFTA and British Comedy Award nominated for Drop the Dead Donkey.

Films include: Beauty and The Beast, Hunky Dory, These Foolish Things, The Pleasure Principle and Remember Me?