In December 2005 the European Parliament approved rules forcing telephone companies to retain call and internet records for use in anti-terror investigations. The law allows records to be kept for up to two year.
Police will have access to information about calls, text messages and internet data, but not the call content.
The UK, which pressed European member states to back the rules, said that data was the “golden thread” in terrorist investigations.
The parliament voted by 378 to 197 to approve the bill, which had already been agreed by the assembly’s two largest groups, the European People’s Party and the Socialists.