Thanks for that! It confirms my long-held but vague impression that the Doctor was genuinely (mostly) getting younger every regeneration, though one or two of them buck the trend... - it would be interesting to see that list in chronological order by Doctor, with start *and* end ages. So - depressingly - going by that, the next actor would probably be aged about 27. Which IMHO is FAR too young.

Hang on, how old is the lad who'd playing Merlin? Given that Gaius looks very like Hartnell (in that wig...), there's a crossover (including T.H. White's Merlin!) handover looming there...