angry tapir writes "Workers at T-Mobile UK have been selling customer data to brokers who worked for the competition, according to T-Mobile and the UK's Information Commissioner's Office. Criminal charges are being prepared. 'Many thousands' of customers' account details, millions of records, were sold to several brokers for substantial amounts of money, the ICO said. In an announcement (PDF) from the ICO, the agency does not name the operator involved, but T-Mobile acknowledged that it had alerted ICO about the data breach. The BBC reports that after the other mobile operators said they were not the subject of the investigation, T-Mobile confirmed its involvement."