Alison O'Donnell has reflected on stepping down from the role of Alison 'Tosh' McIntosh in BBC drama Shetland. Since the show began 13 years ago, Alison has played the dedicated, empathetic detective who has grown from a young junior officer into a seasoned Detective Inspector.Earlier this year, the actor announced she would be leaving the show, with her final scenes taking place in the upcoming 11th season, which begins on Thursday 12 November.