‘Dying. Everything dying. The whole of creation was falling apart, and I thought, there’s no point. No point to anything. Not ever.’ This is a much messier proposition than either The Parting of the Ways or Doomsday. Unlike those episodes, it’s not really built around the departure of a regular character – Martha’s exit comes with the reassurance that she’ll be back, and none of the finality of the ninth Doctor’s, ‘I’m not going to see you again’ or Rose’s last farewell at Bad Wolf Bay. The audience already knew Jack would be appearing in Series Two of Torchwood, and even the Master gets an escape clause as a red-fingernailed hand picks up his ring as his chuckle echoes.

What we get instead is something that is, in some ways, more adult. It’s full of ideas of taking responsibility, of caring for other people. The Doctor’s message to the Master is one of forgiveness and rehabilitation. Jack has a responsibility to his team in the Cardiff Hub, and Martha can’t walk away from her family again, not after everything they went through in the Year That Never Was. Finally, the Doctor has to take responsibility for the consequences of treating Martha like ‘second best’. Life continues, it’s messy, and sometimes there are no happy endings. Maybe that’s the ultimate lesson: at the end of the universe, there is no escape from the darkness.

The inspiration for elements of the finale come from probably the greatest of all the Doctor Who Magazine strips, The End of the Line – in which the last humans trapped in a dying city have to evade cannibals as they seek to repair an underground train to escape to the dreamed-of paradise of the Countryside. This all sounds very much like Utopia. But the grim punchline to the comic sees the fourth Doctor take the TARDIS to the Countryside to meet the people he helped to save – to discover they never made it. That’s the horrifying truth Lucy Saxon perceives at the end of time: no hope, no future, and no Doctor to come up with a reassuring homily. It sounds plausibly enough to drive someone insane.

If that all sounds much too dark, Martha’s mission to inspire hope is a neat counterpoint. Connecting back to The Shakespeare Code, her power is in her stories, not superweapons. The upshot of this, the power of human prayer (and the Archangel Network) converting the Doctor into Space Jesus, is hokey but thematically consistent with the rest of Series Three, where words have often been part of the resolution – against the Carrionites, Martha convincing Joan that Smith was really the Doctor, the Doctor communicating with Sally Sparrow to tell her how to stop the Angels. There was a way to do all of this without the magic angel wings if RTD had just dropped the idea of the Doctor being aged into a wizened pixie, and I find it a bit of a reset too far on top of the paradox machine sending the Toclafane back into hell (in a way that’s pretty much re-used in The End of Time), but I don’t think it’s a showstopper.

And elsewhere, I think this is a strong episode. There is an epic feel to Martha returning to Britain One Year Later, and Agyeman gets some of her best moments with Ellie Haddington’s duplicitous Professor and then later as she’s hiding from the Master as he comes down to Earth to find her. Simm’s also at his best in his confrontation with Martha: the words might evoke Delgado’s ‘Miss Grant’ dialogue, but there’s no warmth or charm in them. But my favourite relationship is between the Doctor and Francine – a few episodes before, she was slapping him across the face. Now, the moment when he hugs her as she stands down from killing the Master, and later the tight little smiles they give each other through the window of the Jones house reinforce the ideas of forgiveness and reconciliation.

All these details, and others like the wild dogs roaming London, the nod to the Genesis of the Daleks dilemma – ‘I’m a Time Lord, I have that right’, Lucy Saxon’s black eye and the Master’s dismissive little push of the Doctor’s wheelchair, make it easier to overlook some of the undercooked elements, like the idea of the Master turning Earth into New Gallifrey at the heart of a new Time Lord Empire – which seems to exist purely as an excuse to have a final countdown, and the cul-de-sac of the Master and Doctor teleporting down to Earth for a chat on a clifftop. You can see the basis of a truly great episode here, but I think the fact that this isn’t truly great shouldn’t obscure the fact that it’s very, very good indeed. Series Three is, for my money, the best of the 21st Century. Its highs, including Gridlock, Blink and The Family of Blood, are some of the best-ever Doctor Who episodes.

Dr Who will return in Time Crash

Next Time: Revenge of the Slitheen – Part One