Written by Ian Scott Stewart
Directed by Ken Turner

Oh dear.  This isn’t very good at all.  Let’s look at some of the problem areas in a bit more detail.

Our old friend the day-for-night filter makes an appearance at the start of the episode.  As mentioned in Identified this is rarely a convincing effect and the bright sunshine here makes it look even more false.

More problematic is that apart from one brief scene with Lt Ellis, the first ten minutes are devoted to guest star George Cole as Roper. Cole’s performance is curiously flat and although it becomes clear early on that he is being blackmailed it’s very difficult to care or feel any empathy for him. His silly haircut doesn’t help either.

The story would have probably worked better a little later in the run, where Roper’s part could have been taken by one of the numerous walk-ons that we see crop up in each episode. At least then there would be a little frisson to them betraying SHADO, as we would have seen them interacting with the likes of Straker and Freeman over several episodes. We’ve never seen Roper before so why should we care about his problems?

Why did the UFO target Roper’s car? Straker seems to believe it was because the information Roper passed on was inaccurate but how did the UFO know that the car was Roper’s? Nice modelwork though, although it does beggar belief that Roper could walk away from the crash with barely a scratch.

And how did the UFO that attacked Roper manage to land on Earth undetected? So far it’s seemed to be impossible for a UFO to land without SHADO picking it up.  The idea that the aliens are recruiting human spies is interesting, but how does it work in practice?  What can the aliens offer in payment?

The rather convoluted plan for the UFO to bypass Moonbase’s defences (thanks to Roper’s information) has been unraveled and Straker’s response is to put Roper on the Lunar surface with a rocket launcher to stop it. Why not put ten, or twenty people, on the surface, so that it wouldn’t be the suicide mission it turns out to be?

And since there’s only a single UFO approaching it’s hard to to understand exactly why there should be so much panic. Everybody does their best to ratchet up the tension, but it all falls somewhat flat. The final shot is quite nice though as it’s another example of how ruthless Straker can be.

With a more charismatic actor playing Roper this might have been a bit better but as it stands it’s something of a damp squib.