Wireless carrier T-Mobile UK has recently admitted that some of its employees have sold customer data to one of the rival networks in the country. The operator announced the UK's Information Commissioner's Office (ICO), and the two entities have been investigating together the allegations. The data sold is reportedly including customers' mobile phone contracts, as well as contract expiry dates.

The sold information apparently went to the service provider's competitors, which then had agents calling users just before their contracts expired so as to offer them new contract options. According to the mobile phone carrier, the account details on a few thousands of its customers have been obtained unlawfully.

According to some of the findings of ICO's investigation, T-Mobile UK's employees have sold the information to a series of brokers, and it seems that considerable amounts of money have been involved in the deal. ICO is already prepping a prosecution file, after obtaining search warrants. According to BBC, a T-Mobile spokesman already confirmed that the data had been sold by their employees, and that the company hadn’t had any knowledge of this.

The Information Commissioner, Christopher Graham, reportedly stated: “Many people will have wondered why and how they are being contacted by someone they do not know just before their existing phone contract is about to expire. We are considering the evidence with a view to prosecuting those responsible and I am keen to go much further and close down the entire unlawful industry in personal data. But, we will only be able to do this if blaggers and others who trade in personal data face the threat of a prison sentence.”

No exact details on the findings have been unveiled for the time being. The T-Mobile UK customer data issue follows last year's data loss suffered by T-Mobile's German division. The wireless carrier is not the only company that faces stolen data problems, and it seems that the main issue is that not all companies ensure that the security of customer's data is at the required levels.