O2 have just completed a test of “near field communications”. It’s the technology used in Visa Paywave cards, Oyster cards, cards that let you into your block of flats, and all sorts of things. A similar sort of thing to the Barclaycard OnePulse card, but they want to put it into your phone so you don’t have to carry around a physical card. Good idea in theory. But what about in practice…?