Derren Brown takes someone's wallet by asking

From psychotherapist Milton H. Erickson's handshake induction:

Confusion is the basis of Erickson’s famous hypnotic handshake. Many actions are learned and operate as a single “chunk” of behavior: shaking hands and tying shoelaces being two classic examples. If the behavior is diverted or frozen midway, the person literally has no mental space for this - he is stopped in the middle of unconsciously executing a behavior that hasn’t got a “middle”. The mind responds by suspending itself in trance until either something happens to give a new direction, or it “snaps out”. A skilled hypnotist can often use that momentary confusion and suspension of normal processes to induce trance quickly and easily.