The revelation that there’s a new, previously unknown version of the Doctor pootling round time and space absolutely floored Doctor Who fans when it was revealed in series 12’s fifth episode Fugitive of the Judoon – but it wasn’t long before they were back on their feet and theorising just how this new incarnation (played by Holby City’s Jo Martin) fits into the established canon.


Was she a version of Jodie Whittaker’s Time Lord from a parallel dimension? A predecessor to William Hartnell’s First Doctor (the original, you might say)? Or is there a more complex way she slips into the Doctor’s timeline?

To find out the truth, we’ve delved in-depth into some of the most popular theories and what counts for and against them. Though of course, given that this is Doctor Who the real answer could be weirder and more wonderful than we could possibly imagine…

1. She’s the real First Doctor

William Hartnell as the First Doctor
William Hartnell as the First Doctor BBC

Is Jo Martin playing the first incarnation of all? There’s quite a few clues pointing to this theory, from the fact that this Doctor calls the TARDIS her “ship” (something William Hartnell’s Doctor was known for), the interior design of the TARDIS itself (which evokes Hartnell’s style despite having a different layout) and this Doctor’s unfamiliarity with the sonic screwdriver.

The First Doctor never used a sonic screwdriver on-screen, only picking it up in the time of his second form (Patrick Troughton), so this could be a big nod towards this being a Doctor before any we’ve ever seen. Arguably, her slightly grumpy attitude also ties her closer to the slightly more crotchety original Doctor, though it’s hard to say that she’s otherwise that close in personality to Hartnell’s incarnation.

More like this

Outside of the recent series it’s also worth noting that Michelle Gomez’ Missy (an earlier version of the Master) once said she’d known the Doctor “ever since he was a little girl.” At the time we assumed it was a joke – but maybe the Doctor’s first form really was female, and the Master remembered it even if he/she didn’t.

As for why the Doctor doesn’t recognise or remember this form, well, it could all be tied into the ongoing Timeless Child mystery. As many have pointed out, Martin resembles the young girl we see during the Doctor’s vision of the Timeless Child back in Spyfall Part Two, and given that the Master (Sacha Dhawan) hinted at some memory-wiping activities when it came to this mystery it’s possible the current Doctor doesn’t remember the truth of the Timeless Child or her former self for the same reason – a plot by the original Time Lords.

So yes, there’s a lot recommending this theory – but there are a few drawbacks to it too. Perhaps most notably, this new Doctor’s TARDIS is already in the form of a blue police box, whereas 2013’s The Name of the Doctor established that Hartnell’s Doctor stole it when it was in its default, metal cylinder mode.

Plus, in 1963’s An Unearthly Child (the original Doctor Who story) it’s implied that the TARDIS’ chameleon circuit only breaks when the Doctor travels back to the stone age in that serial.

Given all this, it seems impossible that Martin’s Doctor could already have the TARDIS in this form if she was genuinely a pre-Hartnell incarnation – assuming that this isn’t just a kink of canon the current production team has forgotten (remember Jodrell Bank?).

Plus, there’s the question of the Doctor’s initial regeneration limit, which was confirmed to have been reached by 2013’s The Time of the Doctor. If this other Doctor had been kicking around somewhere, David Tennant’s Tenth Doctor would have been the last man standing, surely?

In which case, there could be a different answer within the Doctor’s fractured timeline…

2. She’s between the Second and Third Doctors

Patrick Troughton as the Second Doctor (BBC, HF)
Patrick Troughton as the Second Doctor (BBC, HF) BBC

When ex-showrunner Steven Moffat created John Hurt’s War Doctor for the 2013 anniversary special, he exploited a gap within the Doctor’s personal timeline. Specifically, he noted that we’d never actually seen a regeneration from Paul McGann’s Eighth Doctor to Christopher Eccleston’s Ninth Doctor, slipping this new, repressed incarnation in between them and making Doctor Who history.

And with that example in mind, there’s another obvious place where this new Doctor could slot in – between Patrick Troughton’s Second Doctor and Jon Pertwee’s Third Doctor. At the end of 1969’s The War Games, the Second Doctor is forced to summon the Time Lords for help and is put on trial for his crimes, shortly thereafter exiled to Earth with a new appearance (Jon Pertwee’s Third Doctor) which we first see when he stumbles out of the TARDIS.

However, for years fans have suggested the idea that the Second Doctor wasn’t immediately sent to Earth, as we never actually see him regenerate into Pertwee’s version. The “season 6B theory” instead posits that for a while the Doctor worked for the Time Lords under threat of enforced regeneration and exile, as a response to a number of inconsistencies.

To whit, the Third Doctor arrives in the next story (Spearhead) with a number of items the Second Doctor didn’t have, including a ring, a bracelet and a TARDIS homing watch. Later, in team-up stories like The Five Doctors, Troughton’s incarnation knows details about his companion’s fates and shows an odd willingness to work for the Time Lords given his reluctance to call them in The War Games.

1969 RT Jon Pertwee

And most confusingly of all, in 1985’s The Two Doctors both the Second Doctor and his companion Jamie McCrimmon (Frazer Hines) have visibly aged, and The Doctor’s TARDIS looks different. Jamie also has knowledge of the Time Lords he never would have during his own time, given that the Doctor never spoke of them and Jamie’s memory was erased at the end of The War Games.

From these inconsistencies, Who fans built up an alternate continuity that suggested the Doctor was recruited to join the Celestial Intervention Agency, a “clandestine Time Lord organisation” shown in TV story The Deadly Assassin. During this period it’s suggested the Doctor aged, changed his TARDIS, picked up some new gadgets and re-acquired his old companions, and embarked on the stories of both The Five Doctors and The Two Doctors.

So could this new Doctor fit in this gap? Well, it’s possible. Ritu Arya’s character Commander Gat appears to be some sort of Time Lord intelligence officer, which could tie her into the Celestial Intervention Agency, and she notes that she and Lee (Neil Stuke) have the “same training” – could this be from working for the same organisation as the Doctor?

Martin’s Doctor also notes that she’s hiding from a “job” that’s she’s not allowed to leave, which fits with the idea of the Doctor forced to perform missions for this Gallifreyan CIA. Assuming Troughton’s Doctor did do this work for a time, maybe Martin’s Doctor is the one after him, with her memories of those years (and the latter years of her Troughton incarnation) wiped out by the Time Lords.

So yes, this is a fun theory. There are two catches, however – the first that exploiting such a nerdy, specific point of canon might be a step too far for the series (how would you explain all this on-screen?), the second that if she were the “real” Third Doctor there’s be no reason for Martin not to recognise the sonic screwdriver.

Though of course, she might just not recognise Whittaker’s version of it - it's definitely had a bit of a facelift since Troughton's day.

3. She’s a future Doctor


Yes, this seemed to be ruled out in Fugitive of the Judoon – she doesn’t know about either of the two times Gallifrey was destroyed – but if she doesn’t remember being the 13th Doctor either, who’s to say it isn’t part of the same mind-wipe?

Maybe in the future Gallifrey has been restored (again) and the fact of its destruction has been wiped from history, and the memory of her past lives has similarly been taken from this new Doctor. The current Doctor, after all, has a hefty consignment of regenerations ahead of her after Matt Smith’s Doctor got a new set, starting with Peter Capaldi and continuing with Whittaker.

The original 13-regeneration limit has been filled by incarnations we already know about, so unless there’s a whole cycle before Hartnell (which is possible, look at The Brain of Morbius) it seems far more likely this is a Doctor of the future.

The one drawback? It seems unlikely that Chris Chibnall would box himself in narratively by showing who the next (or any future) Doctor would be long before she takes on the series (Whittaker has said she’ll do at least one more after this). With that in mind, it seems unlikely we’ll see Jo Martin as the series lead in Doctor Who any time soon.

4. She’s a parallel universe Doctor


For a while, this was the most popular theory as to how Martin could be the Doctor, especially after the first episode in the series hinted at the possibility of “multiple Earths” during the Kasaavin’s attempted takeover. We’ve seen parallel universes in Doctor Who before, after all – most notably in the 1970 story Inferno and during the 2006 series, in a story involving the Cybermen – and this could be a way of making Martin’s character a different and unknowable Doctor with ambiguous motives.

However, showrunner Chris Chibnall has poured cold water on this idea, suggesting that having a parallel universe explanation would be a cop out.

“The important thing to say is – she is definitively the Doctor,” he said. “There's not a sort of parallel universe going on, there's no tricks.

"Jo Martin is the Doctor, that's why we gave her the credit at the end which all new Doctors have the first time you see them. John Hurt got that credit.”

Now, Chibnall could be lying or fudging the truth here, but somehow we don’t think that’s the case – he’s explicitly suggesting the parallel universe idea would be dramatically unsatisfying, so if that did turn out to be the answer he’d only be talking down his own ideas.

Also, the "multiple Earths" line in Spyfall is explained by the end of the episode as referring to the same Earth in different time periods, so this isn't actually an idea that's been intentionally seeded by the series as some have suggested.

So maybe there's something much darker going on...

5. She’s a Fake Doctor


What if it's all a lie? Perhaps, like David Morrissey’s Jackson Lake in 2008 episode The Next Doctor, this is a fake-out, and it’ll be revealed that this Doctor is some kind of clone, genetically modified weapon or something similar. She has the memories and genetics of the Doctor (Whittaker’s version scanned her and found they were the same), but isn’t actually her. Could be, right?

Well, probably not – we’d refer you back to Chibnall’s comments about her being “definitively the Doctor.” And given how much kudos the Who team have received from casting the first woman of colour as the Doctor, it’s not hard to imagine them getting some blowback from suggesting she’s a fake in a few episodes’ time.

Also, frankly, this would just be a very lame twist. Sorry if anyone had their heart(s) set on it.

6. She’s a NEW old Doctor

Screen Shot 2020-01-27 at 15.33.01

OK, bear with us on this one. Towards the end of the episode, Whittaker’s Doctor notes that “time is swirling around me,” suggesting that big and unusual shifts are happening in the very fabric of the universe - all of which leads us to wonder whether the Doctor’s previously-seen past is being rewritten by some unknown hand.

In other words, Martin’s Doctor is a part of the Doctor’s past who wasn’t there originally, but has somehow been slotted in by a nefarious force able to tinker with reality itself. Yes OK, this sounds a bit far-fetched. But this is Doctor Who! You have to reach pretty far sometimes.

The drawback to this idea is fairly obvious – it’s a bit vague and confusing, and would undo a lot of how the series has presented time travel in the past. But on the other hand Orphan 55 did that just a few weeks ago, so who’s to say that’s something the production team even worry about?


WARNING: Embargoed for publication until 21:00:01 on 26/01/2020 - Programme Name: Doctor Who Series 12 - TX: n/a - Episode: n/a (No. 5) - Picture Shows: **POST TX** **STRICTLY EMBARGOED UNTIL 26/01/2020 21:00:01** The Doctor (JODIE WHITTAKER), Ruth Clayton (JO MARTIN) - (C) BBC - Photographer: Ben Blackall

The more we think about it, whichever way this storyline goes it seems clear that the Fugitive Doctor (or the Ruth Doctor, whatever you want to call her) will in some way contradict some piece of canon – and with that in mind, when it comes to figuring out the truth we have to consider what is actually likely to be explained in modern, mainstream Doctor Who.

In other words, much as we love the series 6B/Time Lord CIA theory, it’s hard to imagine Chris Chibnall throwing the show back to the late 1960s to tell everyone about Patrick Troughton’s exit from the show, the plot of The War Games and why that whole regeneration limit thing didn’t count this one time.

After all, look at the return of the Master. After the irrevocable, final death of Michelle Gomez’ Missy, Sacha Dhawan’s new incarnation just popped up with no explanation – and did we need one? Not really. All audiences need to know is there’s a new Master, and anyone who cares to can try and fill in the blanks later.

With that in mind, what’s the easiest, simplest twist on Doctor Who’s past to explain to a general audience? Aside from her being a fake, probably that there was a Doctor before the First Doctor. Everyone knows the Doctor changes, people probably have more of an awareness of the First in recent years thanks to his appearance (played by David Bradley in lieu of the late William Hartnell) in 2017 Christmas special Twice Upon a Time, and even if they don’t, the idea that this is the original Doctor (or one of many previously unknown) is pretty easy to get across.

David Bradley
David Bradley as William Hartnell's First Doctor

Sure, there’s the regeneration limit to think about, and the issue of the TARDIS’s shape, but Doctor Who has historically managed to clear bigger continuity hurdles than this. If anything, it’s easy to imagine Chibnall not even bothering to lay out on-screen the rules of regeneration limits and chameleon circuits and the like, while leaving things open enough for fans to create explanations themselves for the lingering points of confusion.

For example: maybe in the series we’ll see there were multiple previous Doctors without it being explicitly spelled out that the Doctor was granted a new cycle of regenerations after his/her memory was wiped, even though many fans may draw that conclusion.

Our instinct here is that as much as this new series is tinkering with the Doctor’s past, it’s unlikely to do it in a way that’s alienating to the general viewers. And if that means us all arguing about the Brain of Morbius Doctors again, so be it. Please welcome Jo Martin, the Noughth Doctor…


Doctor Who continues on Sundays on BBC One