Transport for London is reportedly in negotiations with mobile operators ahead of a pilot which will see commuters pay for journeys through their NFC-enabled handsets.
According to the Financial Times, talks have been held with telcos such as EE and Vodafone about testing a system that would require travellers to tap their phones, rather than Oyster cards.
Trial participants would use operator-owned apps that are pre-loaded with money for the pay as you go system. Weekly or monthly tickets could also be introduced.
TfL is already upgrading its readers so that customers can pay for journeys using their contactless bank cards, meaning that the infrastructure is in place for mobile payments.
Shashi Verma, director of customer experience at TfL told the FT: "We are doing some testing to see how the devices perform on the system and welcome any new payment technologies that meet the relevant industry standards and enable sufficiently fast transactions speeds."
The issue of speed has long been seen as a barrier to mobile payments at TfL. In 2012 Verma warned that the read-speed of NFC-enabled mobile devices is too slow for practical use on the capital's transit network.
TfL ran successful tests of mobile access using a Nokia handset as far back as 2007, but Verma said that industry changes since then to switch the secure element from the phone to the SIM has slowed the read speed down to above its 500 millisecond cut-off point.