Why was the Doctor looking for Belinda in Doctor Who: The Robot Revolution?

Arriving on present-day Earth, at the hospital where Belinda Chandra (Varada Sethu) works, he sets about tracking down the nurse, narrowly missing her on multiple occasions.

Following the trail to her home, the Doctor arrives just too late to save her from abduction by androids – giving chase in the TARDIS, he pursues the robots' ship to their home planet, but a fracture in time means that he actually arrives on Missbelindachandra One six months earlier than Belinda and her mechanical captors.

Establishing himself as the planet's resident historian while he waits, the Doctor teams with a band of rebels to fight back against the robots and free Belinda... but why was he even looking for her in the first place?

"I was told about you, by someone – it’s kind of a long story and I’ve got to be careful about timelines," he tells Belinda, all enigmatic. "But he told me your name, that you would be important."

So, who told the Doctor about Belinda and tasked him with finding her?

The answer might lie in the climax of The Robot Revolution – in the episode's final scenes, Belinda causes a violent reaction when her star certificate touches another version of the same certificate (one that somehow ended up in the robots' possession at some point in the future, before later being transported back thousands of years courtesy of the time fracture, where it served as the foundation for the entire society and civilisation of Missbelindachandra One).

To save Belinda from the dangers of unleashing this paradox – two examples of the same object occupying the same space – the Doctor intervenes, his unique Time Lord physiology preventing her from being evaporated.

But he is also somehow inserted into Belinda's history – or, in his own words: "I just went through your entire life like a bullet – you and me, we go back years."

Are we to understand from this exchange that in this moment the present Doctor was transported back in time, where he was able to tell his past self about Belinda and her importance?

This moment isn't portrayed on-screen, but as a theory, it would explain why he was concerned about being "careful with timelines" – already aware that his future self was the one who sent him in search of Belinda.

Or are we yet to discover the identity of the man who shared this conversation with the Doctor?

Again, to quote the Doctor, "there's still a little bit of mystery left" – we don't know how the robots end up with the star certificate in their possession, or why the TARDIS is unable to return to Earth on 24th May 2025, or why Belinda is an absolute physical match for her descendant Mundy Flynn (also played by Sethu in the 2024 episode Boom).

There's also a brief moment towards the end of the episode that may or may not be important, when the Doctor is reunited with his TARDIS after the craft was previously impounded by the robots. "I saw that box in space," says Belinda. "Is that your… TARDIS?"

What's interesting here is that prior to this moment the Doctor never refers to his ship as a "TARDIS" in front of Belinda, only as his "spaceship" – so how does she know that word?

It's feasible, of course, that they shared a conversation off-screen which accounts for this. It's also, quite possibly, just a continuity error. But could it be something more? Does Belinda somehow possess knowledge of the universe that she shouldn't have?

There is one possible explanation for all of this... Remember the character played by Susan Twist last season, who popped up in various guises across time and space only to eventually be revealed as a herald of Sutekh? Could it be that Belinda too is acting as an unwitting herald for a member of the Pantheon of Discord, like Susan and UNIT's Harriet Arbinger?

This theory would explain why Mundy and Belinda are doppelgangers – much like the different characters played last year by Susan Twist – and why she has knowledge of the TARDIS – much like Mrs Flood (Anita Dobson), another character who is set to keep popping up every week in different scenarios... could she too be another harbinger for the Pantheon?

"I can’t help thinking, Bel, that we are meant to be connected," says the Doctor – clearly, there's more to uncover here as the series continues...

Read more:

• Doctor Who's Anita Dobson was "halfway" to guessing Mrs Flood's true identity
• Doctor Who - The Robot Revolution ending explained: Why can't Belinda go home?

Doctor Who continues next Saturday (19th April) at 7:15pm on BBC One, with new episodes available from 8am on Saturdays on BBC iPlayer in the UK. The series will be available on Disney+ outside of the UK.

Dive into our Doctor Who story guide: reviews of every episode since 1963, plus cast & crew listings, production trivia, and exclusive material from the Radio Times archive.

Check out more of our Sci-Fi coverage or visit our TV Guide and Streaming Guide to find out what's on. For more from the biggest stars in TV, listen to The Radio Times Podcast.