The airwaves were a buzz yesterday and bandwidth logged as UK users of the O2 network and licensed carrier piggyback services found their mobile phone numbers displayed in headers to website owners. O2 scurried between troubleshooting and offering assurances they were looking into the matter.

Very late in the day yesterday, O2 issued its formal apology, stating the unauthorized display of private information was caused by a routine maintenance upgrade.

The apology rendered on O2′s blog targets the concern the error caused but did not apologize for the leak itself. O2 may be avoiding direct responsibility with an eye on possible lawsuits regarding the long-standing breach of privacy: The mobile number display has been reported to have existed since at least 2010. O2, however, stated it occurred some time between 10 and 25 January 2012.

The top mobile provider in the United Kingdom stated that the maintenance upgrade inadvertently displayed only the mobile number and not personal information. They did state, however, that they did share information with

“trustworthy”

…third parties. O2 has refused information on what constitutes “trustworthy” status, a list of those organisations or what user data was given to them, also hiding against potential lawsuits against the carrier.

The story broke yesterday on Twitter as one user declared he saw and read the header. He quickly set up a website where others could determine if their mobile numbers were also displayed, and tweets flew for hours as more users discovered their mobile number and complaints aired.

GiffGaff and Tesco Mobile licensed the O2 network, and their users complained as well. GiffGaff created a complaints and update thread on their community forum. Posts there appeared almost as quickly as Tweets did.

The Information Commissioner has stated he will be investigating the matter, which may explain O2′s continued silence on liability and full responsibility.