She has made many films and television programmes, but is best remembered as the evil Livia in the BBC adaptation of Robert Graves’s novel I, Claudius (BBC2, 1976) and for many appearances on the original run of Call My Bluff. She also appeared as Ursula Mossbank, a Tallulah Bankhead-type actress in Goodbye, Mr. Chips (1969); Ann, the unfaithful wife of Alec Guinness’s character George Smiley, in the BBC1 espionage dramas Tinker, Tailor, Soldier, Spy (1979); the queen Cassiopeia in Clash of the Titans (1981); and Smiley’s People (1982), adapted from John le Carré’s novels of the same names. Another popular role was that of Reverend Mother Mohiam in David Lynch’s Dune (1984). Her most recent film is The Gigolos (2006) by Richard Bracewell, in which she plays Lady James.
Phillips’ West End credits include Pal Joey, Gigi, A Little Night Music, and Marlene, in which she portrayed Marlene Dietrich.
She married Peter O’Toole and they had two daughters, Pat and Kate, but she subsequently divorced him. She wrote about this tempestuous period of her life in the second volume of her autobiography, Public Places. She later married British actor Robin Sachs, from whom she is also now divorced.
In June 2000, she was awarded a CBE in the Queen’s Birthday Honours list. She is also a leading light in Social, Welsh and Sexy (SWS), the London-based organisation for Welsh socialites.
She is also a great lover of domestic cats and has written about them in her autobiography and elsewhere.
Siân provided spoken word backing to ‘Between My Legs’, a track on Rufus Wainwright’s 2007 album Release the Stars