Look, I’d want to talk with you about this anyway, simply because it makes me so happy. You’ve seen the video on YouTube and television news of a young child who explodes with excitement that: “The new Doctor Who is a girl!”

The only difference between me and that child is that I said “Doctor”, not “Doctor Who”. And “woman”, not “girl”.

The thing is, I hadn’t realised just how very much I wanted the next Doctor to be a woman until BBC aired that utterly gorgeous one-minute video revealing Jodie Whittaker. And thinking about it a lot since then, I realise that the really key single reason for how much I wanted it was that it was now or never.

Of course it matters that we get a superb actor, as we have with Jodie Whittaker, and of course that should be all that matters. But it isn’t all that matters and I also realised that I would’ve been disappointed with any man. Apparently there are people who are disappointed that it was any woman, but there’s no accounting for folk.

Only, yes, I am a feminist and I do think it is ferociously wrong how few women are in drama – but I’ve always felt that more about the writing than the acting. Yes, no question: I write strong roles for women in my scripts both because it’s right and because so few people do that you are guaranteed to get truly brilliant actors.

Doctor Who, the series, has been just plain wrong in the ridiculously tiny number of women writers it’s had. I do think the show is amongst the very hardest to write so naturally I think the pot of people who can do it will be smaller than for other shows, but there’s no conceivable reason that the proportion of women in that could be as teeny as it has been.

I have not thought it wrong that the Doctor hasn’t been a woman before.

Follow. Alongside the praise the show has got for doing this, it has also got criticism for not doing it before – and that’s the bit I disagree with.

I think people tend to consciously or unconsciously see the Doctor as being a role in the same way that James Bond, Miss Marple, Hamlet and others are. It’s a role that many or even any actor can take on.

No.

This isn’t about the quality of the actor and it isn’t even really about their gender, it’s about the character. The Doctor is not 14 different actors – don’t ask why Whittaker is called the 13th – who happen to be playing the same role. The Doctor is one character.

Think about soaps and the way they will re-cast a role and pretend nothing’s happened. Michelle coming back to EastEnders decades after she left. I’m struggling for another example but there was one in Corrie where a young man has been played by three or four young men. It’s that kind of thing. You are supposed to accept the new face and believe that it’s the same character.

It is the same with the Doctor, except that no new actor tries to completely mimic their predecessor. And then, worryingly, they change into clothes that they’re going to wear for the next several years.

But Peter Capaldi’s Doctor is the same character who used to wear that long scarf. He is the same character who first tried to stop Ian and Barbara from entering what looked like a police box in the 1960s. Actually, Peter Capaldi referred to this in a sweet chat with young fans that I can’t find on YouTube again. He spoke of his predecessors and said with total sincerity that if you look in his own face, you can see the Doctor’s previous selves.

And then in Jodie Whittaker’s announcement press release she said that one thing about taking on the role is that: “It means remembering everyone I used to be”.

So the Doctor is the Doctor is the Doctor. That doesn’t explain why she wasn’t a woman before. But go back to that soaps analogy. Coronation Street’s Ken Barlow is getting on a bit, if they wanted his character to continue they could perhaps recast the part. They would recast it as a man again because it’s the same character, but imagine that they didn’t. Imagine they cast a woman.

A woman taking over Ken Barlow’s role could be done – I don’t think it’s an acting problem at all – but it would have to be done with the most enormous storyline. Barlow would be transgender, it would run for months or more, it would be a gigantic deal within the storyline of the series.

In comparison, all that’s going to happen in Doctor Who is that Peter Capaldi will glow and out of the flame will step Jodie Whittaker. That’s it. On with the show, on with the character.

I think that’s fantastic. The Doctor is a woman, so what? Star Wars: The Force Awakens made me squeeze my cinema seat’s arm rest constantly because it has a lead woman who isn’t allowed to lead for one minute without a male character telling us it’s fine. The film expects us to be amazed alongside the male characters that this Rey is a pilot, for instance. It’s insulting to women, it’s insulting to everyone. I take it personally: it was insulting to me.

Doctor Who won’t do that, you can be sure, and Doctor Who can go straight into new stories without fuss because actually it has spent around five years setting this up.

I think it’s about five years. I’m trying to remember what there was in the fiftieth anniversary special around four years ago but there was something. I definitely remember another Steven Moffat episode where some random Time Lord regenerated into a woman. And of course for a couple of years we’ve had Michelle Gomez as Missy, a truly glorious incarnation of the Master. Funny and likeable and frightening.

Without her, then, and without the small touches through the last few years and, okay, without some pretty heavy-handed hinting in the last series, the change of gender has been made an organic part of the series.

If all of this had not been done, if the show had just decided on a whim to cast a woman, well, I’d probably still be pleased but then it would’ve felt like a gimmick. The show has been accused of doing this because it’s politically the right moment, because the BBC is under pressure about diversity, and if it were just a single casting decision, maybe that would’ve been true or at least partly true.

Instead, this has been worked on for perhaps five years. It has been created in the writing for perhaps half a decade.

That effort, that continued writing effort and talent, seems to me to be being ignored and it seems to me to be worthy of huge praise.

It was now or never and I am ecstatic that it was now. I don’t fully understand why I’m exactly this excited because I don’t know how the Doctor being a woman is going to change the show since this is literally the same character it always was. Each new actor brings something else and the tone of the show changes each time yet somehow this one being a woman makes the show tingle with new energy.

One more thing, just since it’s you. I was trying to explain to a guy why I was so pleased and I ended up focusing on a little half-smile, half-grin that Whittaker gives just after she’s been revealed. It’s when the Doctor sees her TARDIS and somehow it just promises adventure to me.

That’s true, but what I’ll tell you that I didn’t tell the guy is that I also got a ridiculous amount of pleasure writing the words “her TARDIS”.