O2 has finally revealed the reason for the outage, and says it is working on a fix. O2 tweeted: "One of our 3rd party suppliers has identified a software issue in their system. While O2 hasn't explicitly spelled out who this third party is, rumours suggest that it is Ericsson. According to the FT, 'two people directly involved' have revealed that the issue relates to software in the systems provided to O2 by Ericsson. If you've been affected by the outage, we've got a full guide on O2 compensation.

Source: Daily Mirror December 06, 2018 12:30 UTC