Active since 1970, Ayres is well known for her role in the 1997 film Titanic, in which she played Lucy, Lady Duff-Gordon. Ayres has appeared in numerous films and television series, including regular performances in Armchair Thriller, Penmarric, Play for Today, The Bounder, Father"s Day and Trevor"s World of Sport. She has acted in and directed numerous audio plays for Los Angeles Theatre Works and Hollywood Theater of the Ear.
Ayres appeared on the British Broadcasting Corporation One semi-improvised sitcom Outnumbered as Gran in series 3 (2010) for the episodes "The Family Outing" and "The Internet".
She returned as Gran in the first episode of series four (2011) named "The Funeral". Ayres also appeared in the Christmas special in 2012.
In addition to her film and television work, in 2011, Ayres provided voice and motion capture work for Katherine Marlowe, the main antagonist of the video game Uncharted 3: Drake"s Deception, opposite Nolan North, Richard McGonagle and Graham McTavish, and received rave reviews for her performance. That"ll Be The Day.