On 21 March, the following important behind-the-scenes events were known to have occurred:
- 2006 - Rewrites for The Satan Pit known as "yellow amendments" covered Danny Bartock talking about a virus that could defeat the Ood. (DWMSE 14)
- 2009 - The bookstore scene with Verity Newman in The End of Time was filmed even before the cast read-through of the serial. This was because actor Jessica Hynes was only available to film on that one day before she had to fly to New York to film something else.