A Terry Nation script with an indistinct group of enemies with a somewhat interesting plan. Its a shame to not have Lethbridge-Stewart feature in this rare UNIT appearance and frankly Harry Sullivan (who it was nice to see) was grossly underused and given nothing to do.

So much of this tale was stuff we have seen before, most prominently being the cliche ridden "duplicates" plot device featured everything you'd expect - including a Doctor vs. android Doctor fight. Knowing that Terry Nation is capable of something as mind bogglingly brilliant as Genesis of the Daleks, why would he let this kind of material dribble out of his pen? The Androids at points are dressed like the Ambassadors of Death and they shoot out of their fingers like Autons... did Nation have no interest in trying to create something original and sparky?

Despite all this there are moments of fun and brilliance as you'd imagine there would be in a 4th Doctor/ Sarah-Jane adventure. I love them walking around the fake town and The Doctor's realisation that he is surrounded by Androids on a fake Earth on a never ending 6th July.

They hint that Sarah is leaving at the end of the episode. I can see that she's in the next story, I hope they do her final episodes justice.