‘The TARDIS has turned into a helicopter!’ The end point of Season 19’s Liberty Hall attitude towards the TARDIS naturally concludes with randoms wandering in and flying it about. This undermines what should have been a jarringly wrong moment of the Master at the controls. Having unveiled the Master, Grimwade under-uses him: Ainley spends most of this wandering in and out of the TARDIS looking purposeful.

Meanwhile, the regulars get stuck inside the Xeraphins’ inner sanctum, where they learn that an entire race has merged into a gestalt entity which has become corrupted thanks to the interference of the Master. It’s quite a neat, understated reiteration of this version of the character that he repeatedly becomes the snake in the garden – on Traken and Logopolis his baleful influence brings down whole civilisations. Their homeworld has been ‘laid waste by barbarians’, and their adopted planet is going the same way. It’s a shame that, again, the Doctor has to wait for someone to turn up and explain it all, though to be fair he’s already worked out there’s some sort of civil war going on. It means Davison has to spend the whole episode having to look surprised and appalled rather than actually doing anything.

The best bit comes just before the Doctor persuades the dehypnotised crew of GVF to break into the sanctum, when Professor Hayter drops him right in it forcing him to explain the series of unfortunate events that have led two Concordes to get stuck in the Jurassic. Most of the other funny moments are inadvertent, like Michael Cashman’s delivery of, ‘Nyssa and Tegan, dead?’ and Roger and Angela having to battle hallucinations in a very middle class way.

Next episode: Time-Flight – Part Four