O2 has apologised to its 8 million customers cut off in its nearly 24 hour mobile network outage last week. The company has denied that the outage has anything to do with its network upgrades or preperation for the London Olympics.

The company may now face an investigation by telco regulator Ofcom, now admits its is likely to have to pay compensation to customers affected by the blackout.

"We want to restore customer confidence and trust in us as a service provider. For those customers affected by the lack of service, we will be doing everything we can to make it up to them, with more details to follow," a spokesperson told CBR.

He denied the outage was due to any additional Olympic strain on the network, or from any upgrade works related to the event.

"This fault was in no way related to network capacity, coverage or infrastructure failure. This was an unprecedented incident with one of our network systems, which works to register specific mobile phone numbers to the network," he said.

"We have been planning for two years for the London Olympics and have invested an additional £50m our in preparation for the summer. We continue to invest £1.5m in our network every day to ensure we deliver the best possible network experience to our customers."

He also denied that it had anything to do with work surrounding the company’s new network sharing arrangement with Vodafone, and that it doesn’t expect the problem to occur during the Olympics.

"Now that full network service has resumed, we are focussed on identifying the root cause of the incident. We have launched an investigation to find out exactly what went wrong so we can ensure it does not happen again," he said.