One of the things that keeps the sixties era of Doctor Who so appealing is how each story was completely different from whatever had preceded it. The Invasion is a great example of this, the previous story, The Mind Robber was fantastical and dipped the toes of the show into the fantasy genre by messing about with reality. It must have been a little strange for sixties audiences to go from that kind of adventure to the gritty, urban thriller that is The Invasion. In a way The Invasion was a look into the future of the show, as it wouldn't be too long after this story that the Doctor would find himself exiled to Earth and joining UNIT, it is essentially a trial run of the formula that would forever change Doctor Who for the better and it really works. It is also fitting that the monsters in this story should be the Cybermen, their final appearance until 1975 when they returned alongside Tom Baker in Revenge of the Cybermen.
The Invasion is one those Doctor Who stories that were spread across a number of episodes because of production problems. Clocking in at eight episodes in total, it is longer than the seven part episodes that filled the first series with Jon Pertwee and is up there with The Dalek's Master Plan and Trial of a Timelord in terms of story length. It is because of this that I will splitting this review, episodes 1-4 will be reviewed here and 5-8 will be in a second review, a second episode if you like!
However, it is the story's length that is it's biggest flaw. I wasn't bored once during the first four episodes but after that it becomes more of a running around, changing location and dragged out scenes with one group of characters accidently missing the other group, that really start to let this classic story down. I think that a really ruthless edit of the script was really what this story needed to cut these scenes down and still get the great story that is in there across to the audience.
Also watching this story as if it were two feature length movies allows us to see how long the story was dragged out before the Cybermen eventually appear. There are clues beforehand especially from the Doctor who grows more and more impatient with technology and he tells an automated answering machine to shut up and go away at one point. But it's not until the final five or so seconds at the end of episode 4 that the Cybermen finally turn up. I suppose we can find solace in that they have a heavier presence in the second half of the story.