Countdown to 60: "Barcelona!"

"That's the trouble with regeneration. You never quite know what you're going to get..."

The revived series was only three days old when news broke that Christopher Eccleston had already quit the show, and this would be his one and only season. We fans knew exactly what this meant: there would be a regeneration at the conclusion of Parting of the Ways. The only speculation would be how it would come about. We were spared the long, drawn-out, speculation of who would replace Eccleston, as it was very quickly announced that the next Doctor would be David Tennant, who had just starred in RTD's Casanova, and was known to be a great fan of the show.

The event proved to be another act of self-sacrifice - the Doctor saving Rose's life by removing the Vortex from her and taking it into himself.

(Quite why it "killed" him, a Time Lord, when he only held it for a matter of seconds, when she, a mere human, could hold it for much, much longer remains a mystery - or a bit of bad plotting...).

Something else we wondered was: what would the regeneration look like? I'm sure many people assumed that it would resemble most of the previous ones - with the Doctor prostrate on the floor, changing via some roll-back and mix process.

What we got instead was the Doctor standing upright, arms outstretched, as the regeneration took place - an explosive event with golden energy bursting from collar and sleeves. Unlike in the old days, when different directors and production teams came and went over the years, there was no consistency with this - but since 2005 the programme has maintained this explosive process for every Time Lord regeneration (the Master, the General and River Song as well as the Doctor). 

The very first regeneration wasn't even called that. The Doctor seemed to age and tire - probably due to the influence of the peripatetic Cyberman planet Mondas, which was draining energy. (Though he may have already been affected by the Dalek Time Destructor and the life-force draining of the Elders).

The Doctor passed out for a whole episode, then finally staggered out to the TARDIS. The ship certainly played a role in the first change. We saw the lights dimming - with the ones on the console flashing erratically. The controls seemed to move by themselves. The Doctor fell to the floor and his features flared and blurred and there was another man lying there in his place. Not only did he change physically - his clothes changed with him. 

The first regeneration, at the end of The Tenth Planet, is actually the best of the classic series. They spent a long time on the day getting it right. The faces of the two actors line up beautifully, with just the right amount of flare to cover the transition.

Afterwards the Doctor confirms that the TARDIS played a vital role in the process, and he describes it as a form of "renewal" - which led many fans (and official books and magazines) to claim that the Doctor had actually rejuvenated.

When it came time for Patrick Troughton to move on, at the conclusion of The War Games, it was a case of forced change brought on by the Time Lords. Despite his protestations, the Doctor actually complains about the fact that he's known on Earth in the late 20th Century - so is in a small way complicit in his change of appearance. The Doctor appears to be transported from the trial room to a black void (the Matrix?) and he spins round as his features vanish into shadow - leaving him looking oddly decapitated. It's an alarming sight for any younger viewers watching - especially when it leads to a cliff-hanger as we don't get to see him emerge at the other side of the process. We'd have to wait six months to see where this would lead.

The new Doctor - Jon Pertwee - would stagger out of the TARDIS into a new, colourful decade. This time, the clothes did not change with his body.

When the time came for him to leave, we had another regeneration to sit through first - that of his old Time Lord mentor K'anpo. The process was now called "regeneration" for the first time - the term which remains to this day.

The Doctor's regeneration - the result of intense radiation poisoning - is underwhelming. K'anpo had simply cross-faded into Cho-Je, and the same fate befalls Pertwee as he turns into Tom Baker. It's bland and boring, and the two actors' features - and their shirt collars - fail to match up.

This time, the regeneration is "nudged along" by K'anpo / Cho-Je. (Would it not have happened had he not done this - and how did he do this?). Another new thing is that Cho-Je could exist concurrently with K'anpo - being a projection of his future incarnation. Director / writer / producer of Planet of the Spiders Barry Letts would remember this when it came to the next one.

The Fourth Doctor was haunted by a mysterious white figure who watched events - so is known as the Watcher - as he headed towards his regeneration at the conclusion of Logopolis. This figure proved to be another future projection - but of the intermediate stage in the regeneration process rather than his next incarnation. We aren't party to the conversation the Doctor has with it on the bridge over the Thames, but it looks as if the Watcher basically tells the Doctor what's going to happen to him.

After Tom had fallen off the radio-telescope, the Watcher appeared and merged into his broken body. Tom turned into the Watcher, then the Watcher turned into Peter Davison. This was the old roll-back and mix process as used in Planet of the Spiders, but it was made more visually interesting thanks to that intermediate stage, as Davison himself was also seen made-up in mid-change.

Just before the change we also get the Doctor recalling all of his particular companions, as well as his more memorable villains.

By the time Davison left, at the end of The Caves of Androzani, the BBC had more VFX toys to play with, so the regeneration could be made to look more interesting. (This time the cause was a fatal infection, and for the first time the Doctor regenerates as a form of self-sacrifice - as he could have used some of the antidote for himself). 

Visually, director Graeme Harper was inspired by the closing section of the Beatles' Day in a Life, which builds to a chaotic crescendo.

Harper elects to have a mass of visual trickery overlay the Doctor, who once again recalls his particular companions (but culminating in the Master willing him to die). Instead of clips, all the actors filmed these cameos specially, as they were at the BBC to attend the leaving party.

What isn't made clear is just what Peri sees of this process. Does she see what we see (the visual trickery, that is - not the companions, obviously)?

It's the second best of the classic regenerations.

The next regeneration was... problematic - the biggest problem being that one of the two Doctors had been sacked and was refusing to come back and do the changeover. Poor Sylvester McCoy, already lumbered with a dreadful debut story and floundering with no idea how he was going to play this role, was forced to wear a Harpo Marx wig and Colin Baker's clown suit. The features are blurred out by VFX - but the process isn't well done and we can clearly see that it is Sylvester McCoy wearing a Harpo Marx wig...

The reason for the regeneration is just as bad as the execution. The Doctor appears to have simply fallen off his exercise bike after a "tremendous buffeting" (copyright Pip & Jane Baker) courtesy of the Rani.

Pertwee to Baker might be the blandest regeneration, but this is definitely the worst overall.

It looked as if McCoy would never have to undergo his own regeneration into someone else, as the series was cancelled in 1989.

However, come 1996 there was an attempted relaunch in partnership with an American TV company - and it would begin with McCoy in the role. He would get a few scenes before regenerating into his old friend Paul McGann.

The reason this time was a fatal gangland shooting. (Did I mention it was an American co-production...?). The actual "death" though is due to botched surgery as his temporary companion-to-be fails to get to grips with his alien physiology.

For the first time, proper CGI could be employed. McCoy and McGann gurn for a bit, though we also have flashes of electrical energy and the Doctor's body appearing in skeletal X-ray form.

Russell T Davies - recalling the TV Movie - elected to have his new Doctor appear fully formed in the shape of Christopher Eccleston. McGann would not be invited back (yet). 

Dialogue in Rose does suggest that the regeneration has only just happened. Either that, or the Doctor hasn't been anywhere near a mirror for a very long time. The DWM comic strip was invited to feature the regeneration, but they elected not to do so in the end.

As it is, we did finally get to see missing regenerations during the 50th Anniversary celebrations. Mini-episode Night of the Doctor showed us the demise of the Eighth Doctor - victim of a spaceship crash on the planet Karn. The Sisterhood's Elixir of Life, which we already knew could aid regeneration, was employed to turn him into John Hurt - the hitherto unknown real ninth incarnation which even the Doctor didn't talk about. Then, a few days later, we got to see the regeneration which introduced the Eccleston Doctor, as Hurt's "War Doctor" began the regeneration process. The reason was simply, like the First Doctor, that his old body had worn out.

Which brings us back to "Barcelona!". As we've said, the regeneration process has now become standardised since 2005. The Tenth Doctor will manage to control the process (after being shot by a Dalek) - using some of the process to heal his body and syphoning off the rest into a handy (geddit?) biological container. Despite him not changing, this still uses up one of his twelve regenerations.

He will finally bite the dust for the same reason as Pertwee's Doctor - radiation poisoning - and once again it will be through an act of self-sacrifice.

The Matt Smith Doctor then becomes the final incarnation, now that we factor in the War Doctor and Ten's partial regeneration. 

That's based on the Robert Holmes rule of twelve regenerations / 13 Doctors. However, The Five Doctors had seen the High Council on Gallifrey offer the Master a whole new regeneration cycle...

This was recalled by Steven Moffat, and used to give the Doctor his next incarnation, as played by Peter Capaldi. For the third time, the Doctor died of old age, and for the second time he was able to control the process in order to divert excess energy - this time to destroy the Daleks.

The Twelfth Doctor meets his end after being zapped repeatedly by Cybermen (so Mondasian Cybermen have been responsible twice now). Interestingly, we go full circle as he meets up with his first incarnation in Antarctica just as he is about to regenerate.

We then discover that all of the regeneration lore can be thrown out the window, as the Doctor isn't actually a Time Lord at all, was the person who gave the Time Lords their regeneration abilities in the first place - and is really immortal and can regenerate as often as he / she / it likes.

The Thirteenth regenerates after being zapped by an alien energy form whilst it is busy destroying another peripatetic Cyberman planet - its weapon diverted by the Master.

For the first time in a long time, the Doctor's clothes change as part of the process (mainly because RTD did not want to have the Doctor "in drag", trivialising sections of the trans community). (Tom Baker's boots somehow managed to turn into shoes for Peter Davison however - despite the rest of his outfit remaining the same).

This most recent regeneration is odd in that for the first time the Doctor has taken on the form of a previous incarnation (Ten again). He looks the same, but RTD is at pains to claim that this is a new, Fourteenth, Doctor and not Ten back again.

Another thing about this regeneration is that it takes place outside the TARDIS. War, Nine, Ten, Eleven and Twelve all changed inside the ship - with a couple of them actually blowing the thing up (despite the fact that the Doctor is now supposed to be able to control the process to a degree).

The look of regeneration may have become standardised - but there are still variations.

The 60th Anniversary will see yet another regeneration, as we know that Ncuti Gatwa will be making his full debut at Christmas 2023. Tennant is back only for three special episodes, and presumably the next regeneration will take place in the third of them (though we have been told that the two actors do overlap).

As is now the norm, our only interest will be in how the regeneration comes about - unless RTD can come up with something novel in terms of the process itself.