UFO: Identified

'Identified' was the first ever episode of 'UFO', originally broadcast on 16th September, 1970. As you would expect, it introduces most of the characters (at least those that were in place until a six month production break which led to several of the stars finding other work), as well as the basic premise, that Earth is under constant attack from the far reaches of space by a mysterious, advanced alien race and that a hugely expensive organisation, SHADO, has been set up to both combat the threat and to keep the danger a secret from the general population.

This episode also provides us with first glimpses of all the technology invented to battle the extraterrestial menace: Moonbase, the Interceptors, Skydiver, the SHADO Mobiles, all presented in carefully orchestrated sequences with quite brilliant models and effects. If you miss them in this one, however, there's no need to worry, you'll see the same bits again and again and again and again and again...  

Oh, just in case you were wondering why the aliens are crossing millions of space miles to mess us about, the answer is that they are a dying race, sterile and weak, who are only able to survive by constant organ transplants...for them, popping out to Earth, with its compatible, free range life forms, is like a trip to the Co-Op.