The magician approaches a stranger on the street and engages them in conversation. During the conversation, the magician asks the stranger for his wallet. The stranger, with a bizarre glazed look passing over his eyes, complies and hands over his wallet as if it were the most natural thing in the world. The magician then walks away with the wallet, perhaps pausing to pass the hat if there are any spectators.
Derren Brown makes this look like a feat of verbal manipulation, but it is no such thing. Rather, it is a demonstration of simple hypnotism.
Before approaching the stranger, Brown puts a thin layer of pancake makeup on his face to dull his skin's natural sheen. He specifically avoids treating the tip of his nose, leaving it shiny. While speaking with the stranger, Brown slowly sways the tip of his nose back and forth until the stranger is lulled by the pendulum-like motion into a state of near sleep and high suggestibility. It is then just a matter of asking for the wallet (and perhaps other items -- see the last episode of Mind Control in which Brown absconds with a man's pants) and leaving before the stranger wakes up and, perhaps, presses charges.