Keith Alexander in UFO c. 1970
Keith Alexander (born Keith Buckley, February 3rd 1930, and known by that name in Australia) is an Australian-born British actor and voice actor.
He voiced John Tracy and the imposter Carter in the 1968 film Thunderbird 6. He also served as the film's narrator.
A more recent picture of Alexander
Alexander would later go on to voice Sam Loover and numerous supporting characters in the TV series Joe 90 (1968-69). His other Anderson appearances are the 1969 film Doppelgänger, the TV series The Secret Service (1969), and UFO (1970-71) as Lt. Keith Ford.