Swindells said (via
Radio Times): "I feel tremendously honoured to be joining this series with such a talented group of people. Portraying such an interesting man is incredibly exciting and I feel very lucky to be able to do so. It’s going to be an amazing ride."
O'Connell added: "I’m excited to be working on Steven Knight’s bold and ambitious new project with a brilliant director and fellow cast members. Playing the legend Paddy Mayne is an honour. I can’t wait to get stuck into the challenge of telling this story."
Knight also spoke about the "conscious decision" he made to cast young people to tell the subject's stories.