It feels like ages since Jo Grant came into the Doctor's life and began changing things. In those earlier stories, she quite often bears the brunt of his bad temper – and she in turn doesn't quite 'get' him. It's not until Colony in a Space that she can accept the Tardis is real, that he's not a fantasist. And to be fair, even a mad alien scientist in an Edwardian cape is a bit of a leap to one who travels in time and space.
Perhaps it's a change of view for Jo – that scientists can be as heroic and crusading as soldiers. After all, her original ambition, facilitated by her Uncle, is to join the services – and before falling for Professor Jones, she tries dating Captain Yates. (Can't quite see that relationship going places.) Since then, she's been a humanising force on the Doctor, who has generally cheered up and calmed down. In return, she's become a woman of the universe, to the extent that she can reject the Master's hypnotism and generally talk down to him, before walking out of the Tardis doors, alone, into the alien night of Spiridon...
I still don't think she was ever quite on the same page as him though. Not like Zoe, for instance, who bravely stowed away in the Doctor's old sea-chest to discover the Universe. Jo's travels in time and space tend to be accidental and slightly reluctant. She's not fazed by them – she disputes with planetary colonists and rude-looking aliens without hesitation. Jo is always self-assured, passionate and morally certain: to coin a phrase, down-to-earth. But generally that's where she wants to be. 'There's only one little world I want to see right now,' she says, almost wearily, after all the fun on the Planet of the Daleks. 'Home.'
We're so used to show-runners' arcs these days, the original series can seem rather rackety and thrown together by comparison. But this season, beginning with The Three Doctors' liberation of the Tardis and its crew, travels rather satisfyingly to this announcement of Jo's. The Green Death is the story in which Jo Grant leaves not just the Doctor, but UNIT – and if it wasn't for Professor Jones, it might not have been such a clean break. The Doctor is clearly on the threshold of a new life away from Earth, and one feels rather certain that's not a life Jo would have joined him in.
From the Dawning of Aquarius to her stack-heeled boots and now, her passion for environmentalism, she's associated with the here and now. 'Well,' she says about the Tardis in Frontier in Space, with flippant prophecy, 'I'm never going in that thing again.'
Not that she hasn't learned from her adventures. I've reflected a couple of times on the visions of future Earth she's had: over-developed, uninhabitable, unsustainable, even ungovernable, threatened by fear and greed and waste. These are thematic connections rather than literal ones – Jo never even witnesses the ministerial self-interest that hands complete control over to Global Chemicals in Episode Two. But a lot of care has been taken with references back to Jo's arrival. Only the production team of the time and fans of today can really appreciate these: when Jo talks about her job description being 'tell the Doctor how brilliant he is,' for instance, she's quoting a line from three years earlier!
It feels a far cry from some of the 1960s seasons, where individual stories shine but the lives of the regulars – and their ongoing stories – are treated with ambivalence. The overriding feeling with the Jo Grant era, for me, is that the writers believe in the strength of their leads, in the security of this family (in part, because of the actors performances), and enjoy throwing them into new situations. In all the years I've been watching Who in sequence, this is a moment when it really feels like a series rather than a show. It would have made a perfectly fitting last story for the Master, too. As it is, it brings to an end the chronicles of that UNIT family.
What about the Doctor, though? If Jo Grant was a reluctant traveler in time and space, the Doctor has been reluctant to leave without her. After bridling so long at his confinement, it feels as if his main tie to the Earth and his main excuse for not returning to a bootless existence among the stars has been suddenly taken away – and after his solitary voyage to the fabled Metebelis 3 (has nobody ever said how brilliant that planet's name is?) he seems grateful to scramble back to Earth, to a world of mines and silly disguises and mathematical flautists called Nancy. Where exactly does he belong?
Yes, he's changed. He's at risk, you might think, of losing his Doctorishness, his capacity to transcend the present day. Yet that's exactly what his extra-terrestrial, mystical blue sapphire connotes: a very 70s sort of transcendentalism, requiring a physical bauble (whereas in the 60s they just did it, lived it, breathed it) but still effective. His conversations with BOSS, where he seems to take real pleasure in disdainfully scuppering its plans, are good to see and great to watch. And despite the coming departure of his longest ally, Pertwee seems more comfortable than ever in this scene – baiting a disembodied voice (but what a voice!).
So perhaps, he's off too. Perhaps this is just what he needs. But to where, and with whom? Who could possibly take the place of Katy Manning's consummately performed Josephine Grant...?