Deborah was born in Croydon in London. She attended a Quaker boarding school and later studied at the Drama Centre London. She worked in Britain until she toured America with The Beggar's Opera, staying on in Greenwich Village after the tour had finished. She later returned to the UK.She has taken part in productions of Six Degrees of Separation, Thérèse Raquin, The School for Scandal, Hotel Paradiso, and others in locations as diverse as the Royal Court, Bristol Old Vic, the Nottingham Playhouse, the National Theatre and others.She has acted roles in many television productions, including Marta Dorf in the television miniseries Holocaust, Bella Grout in Making Out, and Theresa in A Bit of Fry and Laurie, although she is perhaps best known for her role as the PM's adviser Dorothy Wainwright in Yes, Prime Minister.