Originally Posted by Mulett:
“Also, how did Captain Jack know to search for the Doctor because he had two hearts. Is that a clue, or are we to assume he'd been told during one of the adventures that happened between-episodes. I do wonder about Jack still - how did he recognise the Dalek ships, how did he know they had all been destroyed, and why it is that he's named after a real-life Rose expert.”
Maybe Jack is an agent of UNIT, rather than the Daleks. UNIT know that the Doctor has two hearts, UNIT know about the Daleks - he could have been a time agent for them. Maybe that's how they got time travel technology in the 51st century in the first place.
Their website says they're prepared to go anywhere, anywhen to 'protect' humanity (or something along those lines).
They have been mentioned, in AOL.
Myself, AM and BG speculated a long time ago that it could be UNIT who is the bad guy in all this, wanting time travel technology.
Just another thought to throw into the mix.