Millions of smartphone users in the UK have lost their data services after the O2 network suffered technical problems.
O2 has 25 million customers, but also provides services for the Sky, Tesco, Giffgaff and Lycamobile networks which have another seven million users.
Many users took to Twitter to complain about the difficulties, which were first reported at about 05:30.
An O2 spokesperson said a software issue identified by a third-party supplier was to blame for the outage.
The BBC understands that the supplier is Ericsson, the Swedish firm that has close links with O2’s parent company, Spain’s Telefonica.
“We believe other mobile operators around the world are also affected. Our technical teams are working with their teams to ensure this is fixed as quickly as possible,” O2 said.
“We’d encourage our customers to use wi-fi wherever they can and we apologise for the inconvenience caused.”
O2 is the second-largest mobile network in the country behind EE, which is now owned by BT.
Voice calls on O2 are unaffected by the problem.
The outage is having knock-on effects for other services that use the O2 network, including Transport for London’s electronic timetable service at bus stops, which has stopped working.
Are you an 02 customer who has been affected by loss of data? Tell us about your experiences by emailing
Please include a contact number if you are willing to speak to a BBC journalist. You can also contact us in the following ways:
- WhatsApp: +44 7555 173285
- Tweet: @BBC_HaveYourSay
- Text an SMS or MMS to 61124 or +44 7624 800 100