Reports of problems with a contactless payment system installed at British retailer Marks & Spencer, which led to some customers being charged twice, have sparked a consumer backlash. An online petition is calling for consumers to be allowed to opt out of the scheme and have a transaction card that doesn't feature the near field communication chip and antenna that enable contactless payments. Some particularly concerned British consumers have taken to the social networks explaining how to scrape the NFC chip off plastic cards using a scalpel.Locally, banks and card companies have largely dismissed British security concerns, saying there is no indication that contactless payments are any less secure than payments made with EMV chip cards. They suggested it was likely that Marks & Spencer's management of its point-of-sale system was at fault, rather than the underlying technology.Despite such hiccups, demand in Australia for contactless payments continues to strengthen - with the main action remaining around NFC on plastic debit and credit cards, rather than NFC-enabled smartphones.The industry is somewhat coy about activity statistics - depending on who you ask, there are somewhere between 100,000 and 200,000 contactless-capable terminals deployed nationally.There's also debate about the number of transactions these are handling. Matt Barr, regional head of market development and innovation for MasterCard, said that today more than one in 10 customer-present transactions uses a contactless card. Harry Wendt, Westpac's general manager of digital in Australian financial services, said that he had recently had a meeting with Visa and had been told that one in four face-to-face card transactions was now contactless. Wendt said he would not be surprised if 50 per cent of all face-to-face transactions were contactless within a year.Some businesses are already experiencing this. Coles' supermarkets, for example, recently noted that 50 per cent of all MasterCard and Visa card transactions were now contactless.  Australia seems to be one of the global leaders. Antony Cahill, executive general manager of digital and direct for NAB, said Visa had confirmed that in April it handled more PayWave transactions in Australia than it did across the whole of Europe.Chris Hamilton, the chief executive of the Australian Payments Clearing Association, said that, although he did not have formal statistics about contactless uptake, Australian consumers had rapidly embraced contactless payments, which were, in some cases, starting to replace cash.APCA itself is only an interested observer in the contactless space as Visa and MasterCard operate the contactless network in Australia. Eftpos has also signalled its intention to compete in this space, announcing earlier this month that it planned a trial with C-SAM and intended to bring together a white label contactless solution later in the year.According to MasterCard's Matt Barr: "For us, contactless on cards is preparing the rails for where we see digital payments going." By the end of 2014, all MasterCard cards in Australia will be contactless-capable, he said.Sandy Shen, China-based research director of analyst Gartner, said that contactless cards were now well established and have been used in various sectors and