The UK's Serious Fraud Office (SFO), as reported by the Sunday Telegraph (paywall applies), is investigating some past goings-on at Telefónica UK (O2) well before it became part of Virgin Media O2.Details are fuzzy, but the background – as acknowledged by O2 in the latest Virgin Media O2 financial statement – relates to "possible violations of anti-bribery laws and regulations."O2 said in the statement that it had been addressing a "request for disclosure made by governmental authorities" concerning the possible violations, and that it continues to cooperate with them as part of an ongoing investigation.Since "governmental authorities" seem to include the SFO, the issue necessarily takes on a more serious complexion, at least for those following developments from the outside.An O2 spokesperson told Light Reading (by email) that the operator had nothing to add to the Sunday Telegraph report and declined to make any further comment. The operator is believed to be conducting its own internal investigation as well.Murky past?Industry speculation reckons the government probe can be traced back to 2017 and the sudden departure of two senior executives in that year. The Financial Times points out that the first mention of an investigation appeared in its 2017 accounts.In a footnote to its Q1 2021 results – again, as reported by the Financial Times – O2 said that while it was not possible to predict the full scope or duration of this matter, it "considers it can make a reliable estimate of the outcome and has made an accrual for this amount for the three-month period ended 31 March 2021."Even so, it invoked a clause in accounting rules to keep the amount of the provision confidential on the grounds that "further disclosure will be seriously prejudicial to future developments."— Ken Wieland, contributing editor, special to Light Reading