The problem has also hit customers of Sky Mobile, Tesco Mobile, Lyca Mobile and GiffGaff - all of which use O2's infrastructure.
Earlier today O2 confirmed the issue was identified as a software problem within the system of one of their 3rd party suppliers.
'We have been working hard on resolving the United Kingdom data issue since early this morning.
Angus Council say its meters have been affected by a network problem affecting all of the UK. The service had not resumed by the afternoon.
Borje Ekholm said: "The faulty software that has caused these issues is being decommissioned and we apologise not only to our customers but also to their (other network's) customers".
O2 is investigating reports of issues when using 3G or 4G data, adding that "voice calls are working OK".
The fragility of the increasingly connected systems that keep modern, Western nations running was underlined Thursday when major telecoms network O2 ceased to transmit mobile data from around 0530 GMT.
Ericsson said that, with the cause of the issue now isolated, it was working to get all of its customers back online.
After EE, O2 is the second-largest mobile network operator in the United Kingdom with over 25 million subscribers.
Customers have vented their frustration at not being able to access the internet on their phones. However, some customers are reporting voice issues as well.
The company, the second-largest mobile network in the United Kingdom, said it was investigating the technical fault.
The company have so far not said anything about whether they would be giving customers compensation for the outage. "We are really sorry and working as hard and as fast as we can to fix this".