In a previous post, I waxed lyrical about the vexing question of the Doctor’s age, and concluded that in the classic series he is 450 and in the new series 900 Earth years old, and that all other ages given are in Gallifreyan time.

So, based on these criteria, and the evidence we have on screen, the next question that occurs is – which is the longest-lived Doctor? Based on the evidence, this is the countdown…

11. The ninth Doctor – less than a year

Going by his behaviour in Rose, in which he seems to notice his face for the first time, the ninth Doctor is pretty fresh. And once he’s hooked up with Miss Tyler, the Doctor consistently gives his age as 900. There are no obvious gaps, so it’s possible this incarnation lasts about the same length of time as it takes his one season to pan out. Ultimately, it depends whether you believe it’s this version or the eighth which fought in the Time War, but so far all the spin-off fiction implies it was McGann’s Doctor.

10 (or 2). The second Doctor – about three years (or, possibly, several hundred)

With no obvious gaps for missing adventures – he’s travelling with human beings throughout his tenure –the second Doctor seems to last about as long as his onscreen adventures, three years. Of course, if you buy into Season 6B then potentially he’s the second longest-lived incarnation, which is one explanation for his hairstyle in The Five Doctors…

9. The third Doctor – about five years

Hard to say, because, vainly, he never gives his age. He lasted five years onscreen, and there’s not much to suggest that this isn’t the case. Certainly, for his first three series this Doctor was confined to Earth so there’s no possibility of his ageing significantly in unseen gaps. It’s possible after Jo dumped him he went on a long spin around the universe but there’s nothing to confirm this, and every indication that he burnt brightly, but briefly.

8. The tenth Doctor – six years

Based on the ages he gives, the ninth Doctor is 900 years old when he regenerates, and the tenth says he is 906 in The End of Time, which means the tenth Doctor lives a little fewer than six years. He seems to age about a year per onscreen season – so, by Voyage of the Damned (made at the start of Tennant’s third year) he says he is 903. The “gap year” obviously accounts for a slightly longer time period in which he encounters the Virgin Queen and the Red Carnivorous Maw– thankfully, it’s never revealed if these are one and the same.

7. The fourth Doctor – seven years

Like the tenth Doctor, he seems to age about one year per onscreen season. He’s “something like” 750 Gallifreyan years in Pyramids of Mars, and is no more than 760 when he regenerates meaning that although he’s the longest-serving Doctor by screen time, Tom Baker’s is amongst the shortest lived.

6. The sixth Doctor – over thirty years

The fifth Doctor is about 900 Gallifreyan years when he regenerates, and the sixth makes it to 953. Obviously between Peri and Mel, this incarnation has an extended series of adventures – so if you want to believe in Frobisher, Evelyn and Grant then you just go right ahead.

5. The seventh Doctor – over thirty years

Is unambiguously 953 Gallifreyan years old when he regenerates from the sixth Doctor. It’s hard to say precisely how long he lasts but the supplementary material in the BBC Book Vampire Science implies he’s 1009 Gallifreyan years old when he eventually pegs out. Plenty of time for all those New Adventures, then.

4. The fifth Doctor – about ninety years

Given that Tom Baker’s Doctor is 760 in Logopolis and Colin Baker’s is 900 in Revelation of the Daleks, somewhere along the line either the fifth or sixth Doctors have nearly a century’s worth of unseen adventures. Given that there is no obvious onscreen gap for Colin Baker – he’s travelling with Peri continuously following his regeneration – then the fifth seems to be the likely candidate. Which means either Nyssa is very long-lived (which fits with the 1000+ age of the eponymous Keeper of Traken), or in one of the obvious gaps – let’s say between The Awakening and Frontios when he goes to drop off Will Chandler – the fifth Doctor takes a break from Tegan.

3. The eleventh Doctor – almost 200 years

He’s 907 in his first season and something like 1103 in his second. So far, he’s managed to clock up about 200 years experience and counting without even going a bit grey. At this rate, he’s on track to become the most durable Doctor of all. That donation of regeneration energy from River must have included a healthy dose of Botox and HRT.

2. The eighth Doctor – nearly 300 years

Hard to be certain, but it’s likely that this incarnation lives for a few hundred years despite only featuring in one onscreen story. That certainly gives a lot of scope for all those audio, novel and comic strip adventures. In the BBC Books range he’s trapped on Earth for 100 years after the destruction of Gallifrey, and the Big Finish audios include a lengthy incarceration on Orbis.

1. The first Doctor – about 450 years

There’s no competition. The second Doctor is 450 years old in The Tomb of the Cybermen, and in the absence of any lengthy gaps between stories (he’s been travelling constantly with human companions who haven’t aged), we can assume the first Doctor was about the same age when he regenerated. Which means either he was remarkably well-preserved for a tetra-centenarian, or those faces in The Brain of Morbius really were previous iterations.