Doctor Who: Who is The Lone Cyberman?

“Tell her – Beware the Lone Cyberman,” Jack tells Yaz, Ryan and Graham (Mandip Gill, Tosin Cole and Bradley Walsh).

Realising they don’t actually know who the Cybermen are yet, Jack explains that they’re “an empire of evil, in ruins right now, brought down to nothing, finally. But that could all change.”

Jack then reveals that a mysterious group called “The Alliance” sent something “back through time, across space” to defeat the Cybermen, before being distracted by his stolen ship’s security protocols.

“Tell the Doctor, the Lone Cyberman… don’t give it what it wants!” he adds instead.

“At all costs, tell her….”and at that moment, he’s teleported away, leaving an intriguing mystery about what we can expect from this new storyline.

And speaking exclusively to RadioTimes.com earlier this week, Barrowman shed some more light on Jack’s warning, noting that the Doctor could be tempted to some terrible mistake in the future.

“Well, that's why Jack is there,” he said.

“It's basically to tell the Doctor not to give in, in a way, or not to compromise.”

How Jack knows about this Cyberman is more of a mystery, though Barrowman hinted that his character could have some involvement in this storyline going forward.

“He says 'I'll be watching - if she needs me, I'll be there,'” Barrowman noted.

“That’s kind of his last thing. So it's kind of left on a cliffhanger to see what happens.”

For now, we have a lot to wonder about. Is the Lone Cyberman the battered, broken version we saw in the trailers? And if so, what would possess the Doctor to “give him what he wants” – unless perhaps it was to stop some more immediate tragedy, perhaps the death of someone else?

And for that matter, what is the “Alliance” Jack is talking about? What did they send through time and space to fight the Cybermen? And again, why does Jack know this is so important to the Doctor?

Hopefully, we won’t have too long to find out as the Cybermen are expected to return to the series in a couple of weeks time. In the meantime, though? Time to put aside the Timeless Child conspiracy theory binder and break into a new one…

Doctor Who continues on Sundays on BBC One