The ubiquitous high street chain installed its first contactless terminals courtesy of Barclaycard back in 2008, but it's only in the past twelve months as other banks and retailers have come onboard that the technology has begun to take off, says Pret's director of IT, delivery and support, Andy Chalklin.

"Contactless payments in terms of our overall transactions have gone from single digits of probably between three to five per cent, to about 20 per cent in the last 12 months," Chalklin told UK trade mag Computing.

With a high footfall and fast turnover, Pret remains tied to cash as the preferred medium of exchange, with notes and coins representing two-thirds of its daily takings.

Nonetheless, the company is preparing for the emergence of other cashless payment methods, including Mobile NFC.

"We want to be right at the forefront of it, ready for NFC chips in the iPhone 6, ready for when Google releases its [product with contactless technology in the UK] and so on," Chalklin told Computing. "As a retailer it is faster, it is a guaranteed payment methodology; it is not subject to charge-back from the acquirer, it is accessible as people forget their wallets at home but not their phones. And, from a retailing perspective, it is cheaper at the moment; it is 50 per cent of the interchange rate of any chip-and-pin transaction."