Smartphones 'Too Slow' For London Transport
The use of smartphones for contactless payments on London's transport network will not be allowed until transaction speeds are dramatically increased.
Transport for London (TfL) has modified its reader technology, however pilot programmes have shown the time taken for smartphones to process payments is still too long.
Instead, contactless card systems issued by high street lenders remain as the priority technological advancement ahead of a potential phase-out of the existing Oyster card system.
Contactless payments have been used on buses since December 2012, with more than 11.5 million journeys paid using the system.
TfL is expected to roll out the system to include the Underground, tram, Docklands Light Railway, Overground and National Rail services in the capital before Christmas 2014.
Smartphone use is expected to follow as they make up more than 86% of mobiles now sold in Britain, according to research group Kantar Worldpanel.
Oyster and contactless cards complete transactions within a second, but smartphone comparative speed tests cause delays at ticket barriers.
In a statement to Sky News, TfL director of customer experience Shashi Verma said: "We are continuing to modernise all our transport services to make it easier for customers to do business with us.
"The upgrade to our readers to accept contactless payment cards also makes them capable of accepting suitable payment applications on mobile phones.
"In principle, mobile phones with a Visa, Mastercard or Amex payment application could be accepted on our services.
"At this stage, mobile phones with pre-paid cards will not be accepted. We are testing to see how the devices perform on the system and welcome any innovations which improve the services and choices we are able to offer customers."
Several phone operators have already developed bespoke payment systems, however they must meet TfL's technical requirements.
The Underground currently handles around 3.5 million passenger journeys a day.
More than two billion journeys are made on buses annually and Oyster cards are used for at least 85% of the trips.
But Oyster and contactless payments are not without their own potential problems.
TfL has warned passengers about the risk of "card clash" when tapping in and out of their yellow card readers and barriers, if several cards are in a wallet or purse.
The card readers may reject the attempt, or take a payment from another card - with customers charged for two maximum fares.
TfL advised: "This could happen because the yellow card reader reads one card when you touch in at the start of your journey and a different card at the end when you touch out."