His appearances total over 1,000 credits in the industry as a stuntman, co-ordinator or fight arranger.
His film credits include several Carry On films, Never Let Go, From Russia with Love, Dracula: Prince of Darkness, An American Werewolf in London, Raiders of the Lost Ark, and Highlander, where he played the immortal Iman Fasil.
Diamond's numerous television credits include The Adventures of Robin Hood, The Adventures of the Scarlet Pimpernel, The Adventures of William Tell, Sword of Freedom, The Saint, The Avengers, Paul Temple, Last of the Summer Wine, Heartbeat, and London's Burning.
He was stunt coordinator/swordmaster on the 1990 TV series Zorro and acted in three episodes, two as Sir Edmund Kendall who taught Diego de la Vega (Zorro) to swordfight, and directed eight episodes. This series was filmed in Madrid, Spain for the U.S. ABC Family channel.
He was a regular contributor to Doctor Who in the 1960s, as a fight arranger and actor.