Board Thread:The Reference Desk/@comment-216.186.217.21-20130606050421/@comment-188432-20130607155619

Well, you're both right. The base tune is "All The Strange, Strange Creatures", and that is on the series 3, not the series 4, soundtrack. But it's a rephrasing that's heard in Journey's End, and that exact rephrasing has never been released. The reason it's on S3 and not S4 is because, as the name actually indicates, it debuted in trailers for S3, and was commonly used in trailers on the back half of RTD's run. It underscores adverts featuring both Martha and Donna, for instance. And here.

Still, it's fully in Journey's End, and underscores the final moments of Turn Left, so you'd think that it would be on the S4 soundtrack.

Heck, there's even a chance that it could appear on the S7 soundtrack, since it's quoted in The Name of the Doctor, where Clara goes into the Doctor's time stream, when you her as the waitress and the overlooking Ten at the Library. Also, the very, very beginning of the tune proper — the sort of "sprightly piano" bit — is in the cold open when Clara first talks to One, immediately following the rephrase of "This is Gallifrey".

But currently, the only place to get any version of it is the S3 soundtrack — and even that's not actually taken from anywhere but specially arranged and performed for the album.