Unless you pay close attention to the voice credits at the end of the episodes, you may not have noticed a connection between Captain Scarlet and Thunderbirds. The lady providing the voice of Melody Angel is Sylvia Anderson, and she also voiced Lady Penelope. That's not the only connection between Captain Scarlet and another Gerry Anderson programme. Ed Bishop, who voiced Captain Blue, went on to play Edward Straker (the SHADO commander) in UFO.