Doctor Who: 20 Things You Didn't Know About The Day Of The Doctor
17. Ten's TARDIS Was Only Available For Half A Day
It would've been extremely disappointing if the Tenth Doctor's return didn't also feature an appearance from his TARDIS, but The Day of the Doctor kindly delivered on that front.
It isn't onscreen for very long, and that's because there were some real-world complications that prevented the crew from using it.
At the time, Ten's TARDIS was part of the Doctor Who Experience, which is where they borrowed it from while filming the episode. But because the Experience needed it back, the production was only able to utilise it for half a day.
To get around this, Moffat scripted in the idea of Tennant's grungy coral TARDIS reverting back to the colder, more machine-like Matt Smith version.