‘Back to your echoing void, back to the vastness of eternity.’ It’s easy to focus on the final scene, but it’s just summing up the themes of the story: no-one should have total power, neither the icy Striker, the fiery Wrack, nor any of the Eternals. The Doctor’s defeat of Wrack puts paid to the Black Guardian’s plan to unleash the Eternals’ amorality across time and plunge the Universe into chaos, and his rejection of Enlightenment is a restatement of his basic morality – he wants to see the Universe, not to rule it.

This is a smashing story for all three regulars. Strickson gets to pretend to betray the Doctor, woo Wrack and, in Turlough’s big moment, reject a share of Enlightenment, banishing the Black Guardian into the fire (his switch to negative for these last moments is a neat call-back to The Armageddon Factor). Tegan is a little more passive, but her steadfast rejection of Marriner’s weird obsession (‘What is love? I want existence’), her ‘intriguing’ mental image of the Doctor, and her ongoing suspicion of Turlough give Fielding something beyond just asking questions or being belligerent.

Best of all, the fifth Doctor has never seemed quite so relaxed as when he insouciantly interrupts the Gods of Time, leaning against the doorframe to declare, ‘I’m afraid the Captain can’t be with us… I brought the ship into harbour with some assistance.’ ‘Enlightenment was the choice,’ he says wisely, and the pay-off to 12 episodes of Turlough’s dalliance with the dark side is an emphatic rejection of it. It’s hard to see this as anything other than a total victory for the Doctor: he’s not only rescued Turlough from death, but he’s saved his soul as well. This restores the balance a bit after Adric’s death.

It’s almost a shame the season didn’t end on that quietly triumphant note, as it’s such a nice lead in to the 20th anniversary. After two years of having to play a Doctor who’s “vulnerable” (too often written as hapless), Davison’s finally being presented with material that plays to his strengths of understated heroism, sarcastic wit and bloody-minded determination. I’m certainly glad that – after various production challenges – they prioritised doing this instead of the original version of Resurrection of the Daleks, so the season doesn’t end with another grisly massacre and we hold off for a little longer the period when nearly every story seemed to end with a disclaimer like ‘There should have been another way’ or ‘It’s stopped being fun’. Enlightenment is my favourite Davison so far.

Next episode: The King’s Demons