The two networks, which merged last year and are overseen by parent company Everything, Everywhere, revealed that by this summer and in association with Barclaycard, they will offer a handset that includes a contactless-payment system.
The payment functionality will be provided using near-field communications (NFC) technology that allows users to pay for goods and services by simply waving their handset across a special contactless reader in a store. Google's successor to its Nexus One 'superphone', the Nexus S, was the first widely-available handset to have the technology embedded in the phone. Apple is also reported to be planning to include NFC capabilities in the next-generation iPhone.
The firms said the payment system would be available in more than 40,000 retailers across the country.
"This is the beginning of a revolution in how we pay for things on the high street. It's a cultural shift that is as important as the launch of the personal credit card or ATMs," said Gerry McQuade, Chief Development Officer, Everything Everywhere.
"We're making something that's been talked about for many years a reality and, very soon, using your mobile to buy a sandwich, a cinema ticket or, in time, even something bigger like a computer will simply be the norm."
Orange and Barclaycard first announced their plan to jointly bring contactless mobile phone payments to the UK in March 2009. However, until now, there has been very little wide-spread use of the system in the UK.
O2 trialled a contactless payment system between October 2007 and May 2008. The mobile network worked with handset manufacturer Nokia and Transport for London (TfL) to allow 500 handset owners to travel on tubes, buses and trains by waving the phone near an Oyster Card reader or make purchases under £10 in a number of high street stores including Threshers and sandwich shop Eat by tapping the device on a specially designed console.
After the trial, O2 revealed that 89 percent of participants were happy with the Oyster Card application while 87 percent also claimed their choice of handset would be influenced by its ability to be used as an Oyster card.
"I believe that future generations will find it surprising that early this century we were still carrying separate items to buy goods and to communicate with each other. As payment experts, our role is to make it easier, more convenient and incredibly secure for people to make purchases and manage their money while on the move," added David Chan, CEO of Barclaycard consumer europe.