Earlier today we revealed that the O2 network was down in parts of the UK, now we have come across the O2 blog which answers lots of your question regarding why the O2 network is down and when the networking will be back up and running.
O2 firstly confirm that the problems will affect people in East London, North London, Kent and Sussex, the issues will result in people being unable to make or receive calls and will also affect texts and data. The outage is due to theft and vandalism at one of O2’s operations sites in London.
Currently we have not been told exactly when the network will become fully functional, however O2 has revealed that they want to get it up and running as soon as possible and expect things to be working later today. As we speak engineers are repairing the vandalism and replacing the stolen equipment.
If you check out the blog post for yourself you will see lots of other questions answered, these include when the theft happened, how secure the site was and much more. O2 has said that they will keep updating the blog entry when they have more information to reveal, you can check out this link to see what the service status is in your area.
Also See: My O2 app update for iOS 9 desired