So, given that it's not uncommon for Doctor Who guest stars to return to the show, sometimes reprising their earlier roles and sometimes not; and given that it's even been known for guest stars to return to the show as the Doctor...
...am I alone in thinking that Frank Skinner might make a really good thirteenth Doctor when the time comes? His enthusiasm for the show is obvious (just been watching the Doctor Who Extra from last night).
I mean, obviously not yet - give Capaldi a fair old crack of the whip, fanboy that he is (although I really hope they mellow his character somewhat - I can cope with the Doctor sometimes being cantankerous, abrasive and grumpy, but there've been moments this season where he's been just plain obnoxious and unpleasant...) - but maybe about three or four years down the line..?