In the late 1960s Science Fiction on British TV consisted of Thunderbirds and little else, since Star Trek had not been aired yet,but before that "The Invaders" established a Beachhead on our late night schedules. Aged 8 , i was soon captivated by the story one mans fight to convince the world that aliens were living among us and had wormed their way into the police,government and military and were planning to take over the Earth! This was not easy; the aliens looked and acted like us but required frequent "regeneration" in transparent tubes otherwise they would die,and burn up leaving only ashes. Whenever David Vincent [played by Roy Thinnes] discovered alien installations he would phone the cops,only for the switchboard operator to be alien! By the time the cops arrived only dust would remain and Vincent waswritten off as a nut. The show had strong parallels with Cold War paranoia communist witch hunts but benefitted from fine writing and sparingly used but impressive special effects.Of the videos available in Britain i strongly recommend #1] "Beachhead"[excellent music,great story and acting from Roy and his beautiful guest star Diane Baker] and "The Saucer/The Enemy"[two superb episodes on one vid!].Also, if you can find it,"The Trial" where a human is tried for murdering an alien.The scene with the alien "parents" outside the courthou astonishing-----10/10.