Continuity mistake: The episode repeats the closing scene of "Doomsday", when Donna unexpectedly appears in the TARDIS. However, several details are different. One, the console room is more brightly lit than in the previous episode. Two, the shirt belonging to Rose that Donna finds draped over a railing was not present. Three, the Doctor's coat (draped over a ceiling support) has shifted in place, despite not being touched. (00:01:15)
Continuity mistake: When the Doctor sonics the payphone so Donna can call her mother, he's doing it with his right arm, then it cuts to close-up and he's using his left arm. (00:09:00)
Continuity mistake: In the scene when Donna asks the woman if she could borrow £10 because it's Christmas, you can see that Donna is wearing sports shoes instead of her usual white wedding shoes. (00:10:05)
Suggested correction: No, she's wearing the same shoes if you pay attention.
Never mind - she is wearing running shoes for no apparent reason.
Continuity mistake: The cab Donna's in passes a red vehicle on the bridge. A second later, it's nowhere to be seen looking back. (00:12:15)
Continuity mistake: When the Doctor picks up a mug and a pencil to use as props to explain to Donna how she was pulled into the TARDIS, he is initially holding the pencil by the blunt end. The scene cuts to a shot of his face, and suddenly he's holding it by the sharpened end. (00:28:35)
Continuity mistake: When the TARDIS arrives back from the formation of the Earth, the Doctor and Donna rush out leaving the TARDIS door open. And yet in the very next shot, the door is closed. (00:44:30)
Continuity mistake: When the Doctor is giving the Racnoss Empress an ultimatum, the position of his hands on the railing in front of him changes between shots. (00:48:00)