Do we finally have the answer to why the Doctor regenerates early in Doctor Who series 10?

Specifically we’re talking about Peter Capaldi’s upcoming regeneration, the process by which a Time Lord like the Doctor heals himself from injury while simultaneously changing his appearance and personality, in real life allowing for the recasting of the central character.

Now, we’ve known for months that Capaldi is exiting the sci-fi series in the Christmas special this December, meaning that his regeneration would presumably occur in that episode – but for the last few weeks trailers for the current series have hinted that the change could come sooner, with preview footage showing the Doctor’s hands and face bathed in the telltale golden light that signifies the Time Lord rejuvenation.

Many believe that this early regeneration (which Capaldi has also hinted at in interviews) is a red herring, following in the footsteps of a similar “fake” regeneration by David Tennant’s Tenth Doctor in 2008 episode The Stolen Earth. In that case, the regeneration energy was used to heal the Doctor from being shot by a Dalek before being siphoned off into his previously-severed hand (yep, it’s a weird TV show), meaning that the full change didn’t take effect – and now we’re wondering if the Doctor’s newfound blindness will be healed in a similar way.

Just think about it – we’ve seen regeneration energy used to heal wounds without a full change before (with Alex Kingston’s River Song using her remaining regeneration cycle to save the Doctor’s life in 2011’s Let’s Kill Hitler and the Doctor returning the favour slightly for a broken wrist in 2013’s The Angels Take Manhattan), and Capaldi’s incarnation has even tried to use it to heal someone’s EYES in recent years (when he got a bit pally with Dalek creator Davros in 2015’s The Witch’s Familiar). Given these examples, is it such a stretch to imagine a somehow-botched regeneration giving the Doctor back his ocular faculties without changing his appearance?

Now, we’re not sure exactly how the regeneration could be started and then halted in quite the same way the Tenth Doctor managed it before – the Doctor doesn’t have a handy spare hand any more, remember – but we’re sure some kind of sci-fi jiggery-pokery could be used to explain away the inconsistency.

Maybe the presence of two other Time Lords (Michelle Gomez and John Simm’s different incarnations of the Master) later this series will result in the Doctor picking up a bit of spare regeneration energy, or maybe the fact that he started a whole new cycle of regenerations with this latest form (as seen in 2013’s The Time of the Doctor) means the rules are a little bit fudged when it comes to this latest transition (a concept already hinted at by preview pictures released by the production team).

Either way, we’d say that this face, taken from one of the trailers in what looks like the same room as where the Doctor “regenerates” (note the lamps), could be the face of a man who’s just lucked his way back into being able to see again.

For now, based on preview pictures and trailer footage we’re guessing the Doctor will be left in the dark for a few episodes yet – but if we’re right, we’re sure he’ll find his way back into the light very soon.

Doctor Who continues on BBC1 on Saturday 20th May at 7:25pm