Clyde once guest-starred in an episode of the American sitcom My Three Sons, when Chip Douglas is excited that someone from Liverpool was coming to visit and expected him to be a talented musician, implying the success of the Beatles. (The episode aired during the height of Beatlemania.) He appeared in the BBC TV adaptation of Moll Flanders in 1975, and in 1979 he played Godfried Schalcken in the BBC's television horror story Schalcken the Painter. He is perhaps best known for his portrayal of villainous Austrian Imperial Governor Hermann Gessler in the 1980s action series Crossbow, which incorporated Clyde's ability to convey evil in a distinctly aristocratic way. His other notable acting role was as Dick Spackman in the ITV sitcom Is it Legal?. Clyde also portrayed King Charles I in the BBC series By the Sword Divided (1983–85), which focused on the English Civil War (the beheading of the king is featured in the second episode of Season 2). Clyde also starred as Algernon Moncrieff in 1985 in the Great Performances production of Oscar Wilde's The Importance of Being Earnest opposite Gary Bond as Jack Worthing and Dame Wendy Hiller as Lady Bracknell. In the same year, he played the civil servant Densher in Blott on the Landscape.