O2 has blamed a fault in its network systems for the outage that left tens of thousands of customers unable to access services yesterday and today.
Thousands of customers across the UK are still without 3G, although O2 said the service would be restored this afternoon. Its 2G service was back at 8am this morning (12 July). The operator has been inundated with complaints, particularly through Twitter. The outage could lead to an upsurge in pay-as-you-go sales at rival operators but it is too early to report whether this is the case.
O2 said the fault was not location-specific, nor related to a specific number range, which was why customers were seemingly affected at random. A statement said: 'The fault is not related to signal strength or network availability from our mobile masts, which is why phones may still be showing full signal. The fault is due to a problem with a network system, which works to register specific mobile phone numbers to the network.'
Rival operators speculated the problem could have been caused by a software upgrade, although O2 refused to be drawn on the claims.
O2 said 3G services will be fully restored this afternoon. The statement added that 'a thorough investigation' has been launched.
It is O2's second outage in just under four weeks. In late June, thousands of customers were unable to send texts because of a fault, which was resolved overnight.
Earlier this week, France Telecom experienced an outage that left 26 million customers unable to make calls or send texts for 10 hours. CEO Stephane Richard blamed a software problem on Alcatel-Lucent's equipment for the outage.
A spokesman for the regulator Ofcom said unhappy customers should contact O2, but advised against doing so until the network outage was resolved. If the customer remained unhappy, they could raise the issue with the Communications Ombudsman, who deals with alternative dispute resolution schemes.
Editor: Graeme Neill