Now here is a lovely thing: Next, possibly the world’s least cutting-edge science fiction fashion store, is stocking an extremely credible version of the new Doctor’s striped T-shirt. You didn’t get that with Colin Baker.

But the joy (or, just as significantly, the relative ambivalence) with which Jodie Whittaker’s appointment as the first female Doctor was greeted is encouraging in tricky times, in much the same way as Idris Elba looks like James Bond already, whether or not he gets the job.

Officially, there have been 12 Doctors – all white men – but, depending on how you count, there have been about 45 actors who have played the role in various spin-offs, stage plays and specials. A refresh was overdue.

Of course, not everyone is happy. A handful of angry “fans” have already “reviewed” the new series on Amazon with a series of one-star reviews declaring that Doctor Who is dead, thanks to the “feminazis” and “social justice warriors”. “We have an indifferent actress who wants to push a feminist agenda in the lead role,” says one. This is before any of them have seen it, obviously.

But as Whittaker has said: “There has always been change in Doctor Who; this is just more of it – I want to tell the fans not to be scared by my gender. Because this is a really exciting time and Doctor Who represents everything that’s exciting about change.”

The most extraordinary thing about Doctor Who is its longevity – it is 55 this year, which means that, even though the show is about an alien in a magical box, it reflects our cultural evolution more than any other television programme. The only other series with that kind of staying power is Coronation Street, which is 57 this year.

Elisabeth Sladen as Sarah Jane Smith … the longest-serving assistant. Photograph: Adrian Rogers/BBC

But Corrie is an ensemble. Doctor Who’s setup has always been (mostly) female companions orbiting a male star. That is not to say the women on the show were props. The first producer of Doctor Who, Verity Lambert, was a force to be reckoned with – the only female producer in the BBC at that time, as well as the youngest. She shaped the first companions, the Doctor’s granddaughter, Susan, (it was very clear that there would be no hanky-panky in the Tardis – at least until much later on) and the schoolteacher Barbara to be clever and practical.

They were, however, followed by a spate of pretty, young things who were very good at screaming – Polly and Victoria spring to mind. It wasn’t until the third Doctor, Jon Pertwee, that the series gave us Sarah Jane Smith, the longest-serving and possibly most-beloved companion. A feminist, she was the first companion who held on to her day job as an investigative reporter, although she did have her wobbly moments: “You’re still living in the middle ages,” she said to one woman who was living in the middle ages.

Generally, the Doctors’ attitude towards their assistants was indifferent – as summed up in the fourth doctor Tom Baker’s memorably offhand remark: “You’re a beautiful woman, probably,” even though the second incarceration of the Time Lord Romana, Lalla Ward, would tip the sexless Doctor on his head and marry him (in real life, for about three weeks, but it still counts).

‘Something for the dads …’ Tom Baker as the Doctor with Louise Jameson as Leela. Photograph: BBC

Even as the women changed and grew feistier, some things stayed the same. Tegan Jovanka, the bolshie Australian flight attendant with a life of her own, was a prototype of what today’s companions would become – even if the scriptwriters did have her run around Heathrow in purple stilettos more than was strictly necessary.

There was also the last companion of the “classic” series, Ace, a troubled teen who, unlike her predecessors, fought first and screamed later. Interestingly, the lack of sexual tension between early Doctors and their companions in what was a family show (albeit one that needed “something for the dads”, according to one early producer, to look at, such as sexy, savage Leela) had unexpected consequences. It picked up a large gay following because it worked as one of the only shows on television where the hero didn’t get the girl. It showed a world in which you could beat the baddies and be the coolest person in the room simply by knowing more stuff than anybody else, rather than beating them up. This was new and unusual.

When the show returned in 2005, it was impossible for writers as talented as Russell T Davies, Steven Moffat, Paul Cornell and Rob Shearman not to broaden the scope. The way Davies saw it, having someone travel the universe with Billie Piper and not find her attractive was far more unlikely than, for example, an alien pig crashing a spaceship into Big Ben.

David Tennant and Billie Piper as the Doctor and Rose. Photograph: BBC/Adrian Rogers/BBC

The grand amour of Rose and David Tennant’s 10th Doctor arose, too, from a chemistry that captivated a new generation of viewers and enabled them to adore the idea of Piper going off for the rest of her life with a zombie Time Lord created as a byproduct of a biological metacrisis, all in the name of love.

So the new era was certainly different. When I started writing for Doctor Who in novel form, just before Matt Smith started, I was told to keep the romance out of it (my day job is writing romantic comedy). I nodded solemnly, repeated to myself: “You’re a beautiful woman, probably,” and proceeded to keep any reference to matters of the heart well out of things. Meanwhile, the show took a different line: the Doctor was married off twice (once to River Song, who was conceived in the Tardis, and once to – who else? – Marilyn Monroe). He then spent 45 minutes naked on BBC One in the middle of Christmas Day (because his holographic suit hadn’t worked) while Clara’s family looked on.

Alex Kingston as River Song, with David Tennant. Photograph: Adrian Rogers/BBC

Ironically, though, many of the Doctor’s most successful recent relationships have been platonic. It has been home to the sheer enthusiasm and keenness of Donna Noble – Donna wasn’t there for the dads; she was, as Caitlin Moran said, there for puffing down corridors in Per Una outfits. She was loud, noisy, abrasive and didn’t worship the Doctor an iota. Sarah Jane never stopped being a campaigning journalist. Bill Potts, Capaldi’s last companion, was the first gay female companion, something that had almost nothing to do with what she brought to the show – a shot of adrenaline, as it happens. In the end, the most successful companions, and Doctors, share what Christopher Eccleston, the fabulous ninth Doctor, called the simple desire to “eat life”.

And, from the one or two tantalising details we have seen so far of Jodie exclaiming: “Oh brilliant,” the new Doctor looks to be firmly in this mould. Of course, like most feminists on hearing the news, the first thing I wanted to know was: would the new Doctor’s outfit have pockets? #Pockets immediately started trending on social media as soon as the new costume was revealed: thankfully, it has plenty of space for a Time Lord on the move (plus a bum bag for tampons).

And who is writing the new series? Only Malorie Blackman and Joy Wilkinson, along with a host of young writers. My sense is they will keep as much continuity in the Doctor’s personality as possible. (They could really have some fun with the Doctor’s wife, River Song.) After all, a mild sense of the absurd, intellectual vanity and insatiable curiosity are not notably gendered characteristics. The cultural historian Matthew Sweet sees it differently. “In 2018, I reckon (the Doctor) has urgent work to do. Male anger and self-pity seem to be among the most powerful and dangerous forces in the world: I’d like to see the Doctor tackling that – or at least offering us an escape from it. And I’d like to see her channel a bit of maternal energy, too. In fiction, Doctor Who can sort everything out. In real life, it’s more likely to be your mum.”

A new start … Jodie Whittaker as the Doctor with her new companions. Photograph: Sophie Mutevelian/BBC

The writer and performer Stella Duffy, who is exactly the same age as the show, sees it much the same way as my daughter does: “I grew up with five sisters and one brother and we watched it religiously every week. And, for the first time, the Doctor is me.”

To see the Doctor reflected in all of us; to embody the very best of us; to welcome everyone into the Tardis; to wear our rainbow T-shirts with pride, our hands deep in our pockets. Oh, brilliant.