O2 UK says its restored service to customers affected by a recent period of network downtime. The operator claims the outage affected just one percent of its customer base, and was an unintended side-effect of routine maintenance on its 2G and 3G networks.

"Routine upgrade work on our 2G and 3G networks led to unexpected congestion affecting around 1% of O2 customers. We apologise to those customers and thank them for their patience."

We've confirmed that our own (previously borked) O2 SIM is now working this morning, so hopefully the same applies to others affected by the outage.

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