In 1999, Richardson became known to a young audience as the main character Stephen Tyler in both series of the family drama "The Magician's House" (1999–2000). Following this he played Lord Groan in the major BBC production "Gormenghast" (2000), and later that year he starred in the BBC production "" (2000–2001) (screened in PBS's "Mystery!" series in the US), playing Arthur Conan Doyle's mentor, Dr. Joseph Bell, a role he welcomed as an opportunity to play a character from his native Edinburgh. He once more returned to fantasy in the recurring role of the villainous Canon Black in the short-lived BBC cult series "Strange" (2003).