Doctor Who: 13 Cool Details Russell T Davies Just Revealed About The Stolen Earth & Journey's End
6. Davies Forgot That He Needed To Destroy The TARDIS
Near the start of Journey's End, the Daleks locate and seize the TARDIS, taking it aboard their ship and sending it plummeting down into a massive ball of fiery energy.
The TARDIS - with Donna still inside - begins to burn up and explode, but it's saved from destruction when a clone of the Doctor springs into life and flies it away.
This entire sequence of events is extremely important, for several reasons: it establishes the creation of the duplicate Doctor, it makes the real Doctor think that Donna is dead and his TARDIS is gone, and also... it just looks cool. Unbelievably though, Davies completely forgot that the TARDIS needed to be destroyed when he was mapping out the episode's visual effects budget.
How did that happen? We're not sure. But Davies mentioned that he only had a limited number of shots as a result. Fortunately, the whole thing works very well in the finished episode, with no indication that there were any kind of behind-the-scenes problems.