Striding out on stage to open his show, Derren Brown has an expectant beam on his face. The audience too has high expectations, chief among them that Brown's stride will never be broken, that he will never be wrong-footed.
Knowing how the story ends doesn't affect the audience's ability to welcome, with rapturous applause, the outcome of an illusion. These range from the ability to see through tin foil to unearthing someone's intimate childhood memories. However, being presented with such a constant stream of "Derren-do" is unnerving and can even become tiring as a kind of spectacle-based trance sets in. Though it's nothing, of course, compared with the audience members in whom he manages to induce a state of somnambulism.