The UK's mobile operators have abandoned their plans to implement a mobile network on the London Underground in time for the Olympics next year.
Transport for London had said that a Tube mobile network would be funded through the mobile operators.
"The Mayor and TfL made it clear that, given the financial pressures on TfL's budgets, any solution would have to be funded through mobile operators with no cost to fare or taxpayers. The parties were not able to agree a viable proposal and the project is therefore not progressed at this time," a spokesperson for TfL said.
Although they will not have a network installed by July 2012, the mobile operators - Vodafone, O2, Everything Everywhere and Three - said they hope to implement one "at a later date".
"We have been working closely with infrastructure partners and London Underground for some time with the hope of delivering mobile services to the London Underground and are disappointed that it will not be possible to deliver such services in time for next year's Olympic Games.
"As a group, we will continue to positively explore all other avenues available to us in order to provide a service at a later date," the mobile operators said in a joint statement.
TfL insisted, however, that passengers will still have access to Wi-Fi before the Olympics. It invited telecom companies to tender to provide a Wi-Fi service at up to 120 stations on the London Underground, earlier this week.
According to Financial Times sources, the logistics of installing a mobile network were more complex than they realised. This was partly due to the tunnels being small, but also because as construction could only have taken place when trains were not running.
It has been a bumpy ride for the rollout, as plans for a pilot of mobile phone use on the Tube were also scrapped in March 2009 due to high costs.