 Then, in 2004 he played a role in the BBC series of Anthony Trollope's "He Knew He Was Right".Also in 2004, Alderton starred in the first series of ITV 1's "Doc Martin" in an episode entitled "Of All The Harbours in All The Towns" as sailor John Slater, a friend and former lover of Aunt Joan.He played Christopher Casby in the 2008 BBC adaptation of Charles Dickens' "Little Dorrit".