Doctor Who: 9 big questions we have after Orphan 55

But by the end of the episodes, not every mystery was solved. How exactly did Earth become this hostile new planet? Is that contradicted by what Doctor Who has shown us of Earth's future before? And just what were the Dregs planning anyway?

We break down some of the biggest questions - and note a few little nuggets you might not have spotted on your first watch - below.

What is the Doctor “mardy” about?

Near the beginning of the episode Yaz (Mandip Gill) notes that the Doctor has been a bit “mardy” in their recent adventures, only for the Doctor to deny she’s in any sort of mood. “That’s us told!” notes Ryan.

So what’s caused the Doctor’s grumpy attitude? Well, the destruction of her entire planet (again) and civilisation (again), as revealed in previous episode Spyfall Part Two might have left her slightly off her usual game. Plus, The Master’s (Sacha Dhawan) revelation about Gallifrey’s dark secret and the Timeless Child lie could be keeping her a bit preoccupied, just like all of us at home.

In other words, the Doctor’s worried about the series arc, which is how it should be. And all the holiday spas (deadly or not) in the universe are unlikely to cheer her up from that. Huw Fullerton

Have we seen those teleporting cubes before?

The “teleport cube” made up of coupons that Graham (Bradley Walsh) assembles to send the gang to tranquillity spa is actually a new piece of tech for Doctor Who, though it bears some similarities to a classic gadget.

Before the episode aired, we speculated that the cube Graham is holding in the picture could be a hypercube, a flying, glowing cube that Time Lords use to send messages to each other which first appeared during the era of Patrick Troughton’s Second Doctor and returned in 2011 Neil Gaiman episode The Doctor’s Wife.

As it turns out this wasn’t the same sort of cube, though the way that Graham assembles it is rather similar to the way Troughton’s Doctor puts together his hypercube (albeit telekinetically) in 1969's The War Games, so it could be a bit of a mini-Easter egg. HF

How was Orphan 55 Earth all along?

In a scene straight out of Planet of the Apes (or to be even more nerdy and specific, its 1970 sequel Beneath the Planet of the Apes), the Doctor discovers a discarded sign written in Russian, revealing that Orphan 55… was Earth all along!

Exactly what happened to our planet to transform it into an uninhabitable wasteland inhabited by the Dregs is never clarified, though a brief telepathic communication between the Doctor and a Dreg shows us brief, flashing images of devastation and explosions (likely nuclear). Those maniacs. They blew it up.

“How did the Dregs get here? When did the planet get invaded?” asks Yaz – but in fact, the Dregs are a mutated form of our own race… literally the dregs of humanity.

We’ve been here before in Doctor Who, with the show offering a variety of various (mostly unpleasant) ultimate fates for mankind… including becoming the Toclafane from 2007’s Utopia/The Sound of Drums/Last of the Time Lords. Morgan Jeffery

How does Earth’s destruction fit with Doctor Who history?

The future looks equally bleak for the planet Earth, which - going by Doctor Who stories past - will be subjected to two Dalek invasions, devastating solar flares, a new Ice Age, World War VI and finally its total obliteration in the year 5 billion. We’ve gone into a bit more detail about the planet’s grim future as predicted by Doctor Who here.

Regarding the events of Orphan 55, it’s not entirely clear when Doctor Who’s latest trip to a future Earth takes place, or how it fits into the previously established list of devastating events described above. Sometime in the 51st century, maybe? Post-World War VI?

It’s important to remember, though, that this is only “one possible future” and the “the future is not fixed” – possibly much of what’s outlined above no longer happened (or rather, will no longer happen) because of changes to history. MJ

Was that Ben Fogle’s mum?

Yes indeed – the ill-fated Vilma is played by Julia Elizabeth Fogle, mother of TV presenter Ben Fogle (Countryfile, Countrywide, Britain’s Favourite Dogs).

Known professionally as Julia Foster, she is a well-established star of stage and screen – her film credits include Alfie (1966) opposite Michael Caine and she played the title role in the BBC's 1975 production of Moll Flanders.

Her beloved Benni is played by Col Farrell, who, as far as we can tell, is not a close relative of the other Colin Farrell (though did presumably abbreviate his name to avoid confusion with the Hollywood star). MJ

Was that Roger from His Dark Materials?

Yes – anyone missing the BBC’s adaptation of Philip Pullman’s acclaimed novels will have been happy to see actor Lewin Lloyd back on Sunday-night telly. The former Roger Parslow plays wannabe young mechanic Silas in Orphan 55, and ends up with a much less grim fate than Roger at the end of the episode.

We recently had a chat with Lewin about his time on Doctor Who, and you can read it here. HF

Does the Doctor breathe oxygen?

Much of Orphan 55 hinges on depleting oxygen resources and a race-against-time before the air runs out, with the Dregs being unaffected since, as the Doctor discovers, they breathe in carbon dioxide and breathe out oxygen, “like a really angry tree”.

The Doctor herself is seen struggling for breath at points… odd, given that it’s been established in the past that Time Lords can survive without oxygen for much longer than humans – this comes up in stories including 1975’s The Ark in Space, 2007’s Smith and Jones, 2014’s Mummy on the Orient Express and… erm… 2017’s Oxygen.

The fifth Doctor (Peter Davison) claimed to be able to store oxygen for several minutes in 1984’s The Caves of Androzani… so what’s up with the gasping Doc we see here? Respiratory bypass system on the blink? Sympathy suffocation? MJ

Wait, were the Dregs just carrying Benni around that whole time?

One of the big driving points of the episode was the disappearance of Benni (Col Farrell), the longtime partner of Vilma who was taken outside of the Tranquility Spa complex during the Dreg attack.

With the tracking beacon showing he was still outside and moving fast, Benni’s fate inspired the other survivors to head out into the wastelands to look for him – and later on he did return, speaking to Vilma from outside their vehicle and asking her to both marry and kill him (classic romance).

But here’s where we get a little confused. After immediately murdering every other guest at the Spa where they stood, why did the Dregs just decide to sort of… carry Benni around with them? What was the point?

It’s sort of alluded to that they had maimed him and were prolonging his suffering, but he was a sick old man on oxygen. Realistically, how much damage could they have done to him before he died anyway? He was still perfectly lucid and able to speak, after all.

And how did they even do it anyway? Did the Dregs cradle Benni in their arms, drag him along the floor, whip up some sort of stretcher – what? Who carried the oxygen tank along behind him? WHY WOULD THEY DO THIS? What’s the point? Sadly, we’ll probably never know. HF

Has Doctor Who changed the rules of time travel?

Bit of an abstract one this, but the Doctor’s speech at the end of the episode – where she appeals to her companions not to despair at Earth’s future, because they can still change it – sits a little oddly.

“I know what you’re thinking – but it’s one possible future. It’s one timeline,” Whittaker tells her friends.

“Unless people face facts and change, catastrophe is coming. But it’s not decided. You know that. The future is not fixed, it depends on billions of decisions and actions, and people stepping up.

“Humans. I think you forget how powerful you are. Lives change worlds. People can save planets, or wreck them. That’s the choice. Be the best of humanity,” she concludes.

So far, so Green and inspiring. But in this speech the Doctor is also giving a pretty different presentation of time travel than Doctor Who has in the past, implying that it’s possible humanity will avoid this terrible fate if they pull their socks up even if no changes are made from outside the timestream.

Doctor Who has often made clear that “time can be rewritten” – but until now, we’ve always seen somebody holding the pen. Yes, history can be changed and the future altered, but in Doctor Who past that’s always been because of some outside force from outside established events arriving to change things.

In other words, the course of events could only be altered by someone or something – the Doctor in her TARDIS, time-travelling aliens or whatever – arriving from outside those events, from a different timestream. If stuff just changes anyway, wouldn’t Sheffield be different every time the TARDIS team returned home?

Maybe we’re overthinking this, but either way we hope this particular change isn’t one Doctor Who keeps on for future episodes. HF

Doctor Who continues on BBC One on Sundays