With his time as showrunner and head writer on Doctor Who now up, Steven Moffat has been looking back at his time on the sci fi series and musing some what might have beens on Doctor Who The Fan Show.
One that such 'might have been' that will probably interest fans of David Tennant the most is what would have happened had David Tennant stayed on for Series 5. Something that Moffat says David "Thought very hard" about doing.
"David was just going through the, now, to me, very familiar angst about leaving," Steven says. "I went to talk to David and I ran him through what that series would be if it was him."
David did said that if he stayed it would definitely be his final series so Steven ran him through the plot for what would have been the last outing for the Tenth Doctor.
"My version of that series would be that the David Tennant Doctor would crash into the back garden about to regenerate, and little Amelia would help him back to the TARDIS and he'd fly off.
Then she'd meet him again, when she grew up, but he'd have no memory of that because we come to realise that was the Doctor from the future – we'd make our way through the series to the point where the Doctor gets back to that."
As history tells us, David of course decided to move on and Matt Smith took on the series which heralded a lot of changes for fans of the show, from the Doctor and his companion, to the logo and the theme tune, even new look Daleks were brought in.
"David and Catherine (Tate) were leaving, everything was changing and the best way to conceal that level of change was to change everything. If everything changes, it looks like a bold new decision and a new era. Frankly, if David and Catherine had wanted to continue, I wouldn't have done that. It would've been the same TARDIS because there was no way that version of the show was worn out."
Watch the full episode of Doctor Who: The Fan Show below: