Haven't seem the show - but did he predict it before each ball was drawn? It could be a simple trick I suppose, the lottery isn't exactly live - there's a delay or something (or they set one up) and he worked inbewteen that delay maybe?
I'll make sure to ask the new physics teacher on monday, the persons an absolute genius with an interest in those sort of things - he might have figured it all out.
Already posted a video at the top showing the whole thing.
But saying the lottery isn't exactly live

There's like a delay of 2 or 3 seconds. Not only that, the lottery is on BBC and Derren Brown was on channel 4. The BBC seemed reluctant enough to work with channel 4 at all. They were only just allowed to show the BBC on CH4.
Really, the idea that it was all a trick and a lie, and that he was fed the information. Would the BBC or the lottery really want to be involved in something like that. Faking a lottery prediction. I think not. These companies care about their image, and don't want to be seen as deceiving the public.