Now showing on BBC website:: O2 mobile users suffer network problems across UK Man walks over O2 logo O2 says users in England, Wales, Scotland and Northern Ireland have been affected Continue reading the main story Related Stories O2 owner Telefonica profits halve O2 apology for mobile disclosure O2 customers cut off by thieves Thousands of O2 mobile subscribers have lost voice and data services across the UK due to a problem with the network. The firm said that it had begun experiencing issues "at lunchtime" but was unable to explain the cause. GiffGaff and Tesco Mobile customers - who also make use of O2's masts - have also been affected. O2 said the problem is not based on geography. Some subscribers still have connections at the same location as others who do not. A statement on the firm's website said: "Those customers affected will have difficulty making or receiving calls, sending texts or using data. Our engineers are dealing with the problem as a priority and we hope to restore full service as soon as possible." Many users wrote messages on Twitter to complain about the issue. "Starting to get silly now, six hours without service isn't good enough in this day and age," wrote Coronation Street actor Chris Fountain. "Leaving you the first chance I get," messaged another of the firm's customers. But others said they were unaffected. "Everyone's complaining about O2 reception, mine's been working fine all day," wrote one user. Customers have been told they can keep track of developments via O2's service status page. Some have complained that the page is slow to load and sometimes fails to appear. A spokeswoman for O2 apologised and said the site was facing high demand