Does this clue from Doctor Who The Witch's Familiar mean a Dalek-Time Lord hybrid already exists?

And although most of what he told the Doctor during their dangerous liaison turned out to be a lie, the Time Lord seemed to recognise this prophecy about his home planet.

What is the Dalek hybrid, we've been asking ourselves since then, and can you rely on a Gallifreyan prophecy anyway?

It seems strange that a race like the Daleks – who have even destroyed each another for being of impure lineage – would ever want to adulterate their genes with those of another species. Then again, they do love power and what could be more powerful than a Dalek-Time Lord cross?

Exactly what kind of creature that would create it's hard to say – a Dalek with the power to manipulate time (and perhaps regenerate itself) is certainly a terrifying thought – and if Davros thinks it's a good idea, it's probably not...

He certainly got very excited when regeneration energy began to flow into his creations. And the Supreme Dalek's cry – "We are renewed! We are more powerful!" – struck fear into the heart.

Thankfully (sadly?) we never got to find out exactly what a hybrid might be capable of because the energy that was transferred from the Doctor to Davros and his entire Dalek army also reanimated the festering remnants of the countless discarded Daleks that had been cast into the sewer/graveyard below the Dalek city. The slimy mass of "very cross" Dalek juice surged up the pipes, overcoming the Daleks and apparently destroying the city – and with it, we presumed, the threat of the Dalek-Time Lord hybrid.

But is it quite as simple as that? (Let's be honest, in Doctor Who, it rarely is). Just before the Dalek undead rose up, we saw countless Daleks receiving the Doctor's regeneration energy while flying ("elevating", I suppose) high above the Dalek city. We had seen a similar shot of them going about their Dalek business when the city was first revealed and we know from other episodes that, these days, where there's a gathering of Daleks, plenty of them are in mid-air at any given time.

But if all those Daleks were airborn when they absorbed the Doctor's regeneration energy, surely they were also safe from the tide of liquid Dalek that overtook those on the ground.

And surely that would mean that not only are there surviving Dalek-Time Lord hybrids... but that there may be a whole army of them out there.

That of course depends on what effect the Doctor's decision at the end of the episode – to return and save the young Davros – had on the course of history. Did the compassion he showed turn Davros from his original path, meaning the Daleks never existed, or did shooting the "handmines" that surrounded him with a Dalek gun while repeatedly shouting "Exterminate!" simply give the kid ideas?

If it's the latter, the Doctor better hope the Daleks inherited a good dose of mercy with the rest of those Time Lord abilities...

Doctor Who continues on Saturday at 8:25pm on BBC1