George Murcell (Diamond) provided the voice of Professor Rudolph Popkiss in earlier episodes of "Supercar", while Graham voiced parts in "Stingray" and "Thunderbirds".
George Murcell (as gang chief Diamond) provided the voice of Professor Rudolph Popkiss in earlier episodes of "Supercar". Meanwhile, Graham voiced parts in "Stingray" and "Thunderbirds".