Ninth Doctor
The Eighth Doctor regenerated into an individual who would logically have been called the Ninth Doctor after he broke his bones falling back into the Doctor's TARDIS from the eyrie on which he had activated the Moment, destroying the Time Lords and ending the Last Great Time War.
Once the regeneration died down, the Doctor, his thirst for life renewed despite the horrors he had witnessed, eagerly felt at his new face before exclaiming his first word: "Blimey!". (PROSE: Doctor Who and the Time War)
Behind the scenes
In the Instagram release of Russell T Davies' short story Doctor Who and the Time War, he liked a comment suggesting that, as the Ninth Doctor in that story was not explicitly identified, it could be any of the Doctor's ninth incarnations, including Rowan Atkinson's, but since this wiki does not consider Fatal Death parody valid it would be more correct to refer this version.
