The Invisible Enemy
After the promising start made in Horror of Fang Rock, many viewers would no doubt have entertained hopes that the quality of the fifteenth season would match that of the fourteenth. Such hopes would have been soundly dashed by The Invisible Enemy, which is one of the weakest stories of the fourth Doctor's era. Reviewers over the years have struggled to find a good word to say about it. 'The basic idea behind this story of an enemy invading from within the human nervous system was an interesting and novel one,' conceded Howard D Langford in TARDIS Volume 3 Number 3, dated May/June 1978. 'However, having said this, the story was handled badly. The action seemed to be at too fast a rate - I preferred the slower tempo of Horror of Fang Rock.
The introduction of K9 was a disaster which led to inevitable tedious fighting. If we want lasers blasting we can watch Star Wars, not Doctor Who... Finally, the blowing up of the nucleus was the sort of action that the Doctor deplored in Doctor Who and the Silurians, yet here we find him resorting to destruction Ó la Leela. He was supposed to be educating her, not vice versa!'
A particularly notable aspect of this story is its heavy reliance on visual effects. The model shots are the most extensive and ambitious to be featured in the series thus far, and are undoubtedly one of the highlights of the production. Even they have come in for criticism, however. 'It was the visual effects that spoiled the show,' argued Kevin Davies in Quark 1, dated November 1977. 'The spaceship models were excellent... but were reduced to "things on strings" once on screen. The Titan base was straight from Space: 1999, and its eventual destruction was awful. Blaster rays issued from anywhere but the gun nozzles, CSO screens looked unconvincing, as usual, and K9 fired at a pre-cracked wall in order to make a barrier small enough for a puppy K9 to jump over.'
In fairness to designer Barry Newbery, whose characteristically excellent work is the other highlight of the production, it should be pointed out that the pre-cracking of the wall fired at by K9 was successfully disguised when the scene in question was first recorded; unfortunately director Derrick Goodwin called for retakes and the broken section of the wall had to be replaced with insufficient time available for the join to be repaired.
The scenes in which the clones (or rather pseudo-clones, complete with clothes, produced by something referred to as the 'Kilbracken technique') make their way through the Doctor's body are highly reminiscent of the 1966 Twentieth Century Fox production Fantastic Voyage. They work nowhere near as well, however, owing partly to the fact that, whereas in the film the voyagers had a ship with its own atmosphere, here the clones are moving about as if they are in the open air, and partly to the fact that on Doctor Who's relatively small budget the effects that could be achieved were visibly inferior. These scenes are nevertheless some of the more successful ones in the story - although the appearance of the human-sized version of the nucleus of the Swarm at the end of Part Three is very much a let-down, as Keith Miller pointed out in Doctor Who Digest Number 8, dated April 1978:
'I really liked the scene when the Doctor "short circuited" his liver to save Leela from the balloon-type antibodies. The chasm between the brain and the mind left a lot to be desired, but who knows, perhaps such a thing does exist... The meeting between the Doctor... [and the nucleus] was very good, expertly written and acted. However, it isn't long before the nucleus escapes through the Doctor's tear duct and enlarges into one of the funniest Doctor Who monsters I've seen in a long time...
'The remaining struggle to get back to the hive and its inevitable destruction [were] quite well done, but all believability was gone because of the farcical monster. Pity. I had enjoyed the other three episodes.'
Writers Bob Baker and Dave Martin seem to have developed a liking for giving their characters 'catchphrases'. In The Hand of Fear it was 'Eldrad must live!', this time it is 'Contact has been made!' (and later in the season in Underworld it will be 'The quest is the quest!'). Unfortunately this is one of the few memorable aspects of the scripts, which generally consist of clich▀d and undemanding action-adventure material. We will leave the final word to the particularly unimpressed John Peel, who wrote in TARDIS Volume 2 Number 8 in 1977: 'The production team seem convinced that Doctor Who is really a kid's show, and have proved it so admirably with the latest serial. Despite superficial glitter, good miniatures and Frederick Jaeger's superb acting [as Professor Marius] (didn't seem a bit like Sorenson [in Planet of Evil], did he?), The Invisible Enemy failed miserably as entertainment... The Doctor now has a mechanical pet to go with his savage. With stories like this one and Horror of Fang Rock, why not a new time slot as well? Straight after Watch with Mother. The [series] is going to the dogs!'