O2 Mobile Phone Numbers - No Tesco Mobile Network Signal Not Working

It appears that O2 have another signal/network problem with numbers not working - apparently affecting phone numbers across the UK as it isn't limited to a specific region.

The details are on the status page of the O2 website but hopefully will not be as major as the outage in July 2012 that affected millions of users over 2 days.

You can read about the O2 Network downtime in July 2012 here