In his latest stage show, Svengali, Derren Brown is (as usual) asking the audience not to tell others what happens in the show. Consequently, the internet is full of very vague reviews of the show. But we can glean one key detail from bliter's account of the show:
Svengali is an "automaton" that reads minds. This is reminiscent of the televised DB trick in which he pretended to be a mechanical mind-reading device. Here, though, obviously Derren will be outside of the machine. Thus, a stand-alone machine will somehow be made to reveal details about audience members.
It's kind of odd that DB would choose to use a prop as the centerpiece of his show -- but that simply implies that it is an unusually impressive prop.
For a full explanation of what we know about Derren Brown's Svengali, see my article: "Derren Brown Svengali Spoilers."
And to read all about Derren Brown's career, see my unauthorized biography of Derren Brown.