One of the UK's most respected actresses, Dame Harriet Walter is currently enjoying great success with recent appearances in hit TV shows such as Succession, Killing Eve, The Crown and Downton Abbey as well as Ridley Scott's latest film The Duel. She talks with Catherine Fairweather about playing 'nasty characters', the secrets to ageing well, the perks of getting married in your 60's and why British stage actors do so well in Hollywood.