O2, a division of Spanish telecommunications giant Telefonica, said the same problem has also hit other mobile networks around the world.

"We're aware that our customers are unable to use data this morning," an O2 spokesman told AFP.

"One of our third party suppliers has identified a global software issue in their system which has impacted us.

"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."

The spokesman added: "We'd encourage our customers to use wifi wherever they can and we apologise for the inconvenience caused."