Campaigners are opposing plans drawn up by Ireland, Britain, France and Sweden to retain private telecoms information to combat terrorism and organised crime.
The proposals at talks in Brussels today are for EU-wide rules on exactly what details of phone and computer communications should be retained, and for how long, to enable police and security forces to track telecoms traffic.
British officials said the content of communications was not being targeted, but the time and place of phone calls and text messages, and of e-mails and Internet use could be vital in establishing criminal movements and chains of contact.
However, British MEP Sarah Ludford said the proposals threatened civil liberties because they required the mandatory, systematic retention of telecoms traffic data "so that police or intelligence agencies can later seek access long after the data should be deleted under EU telecoms privacy law".
She also opposed separate plans being discussed at the talks on compulsory inclusion on all EU passports of biometric data, including facial scans and fingerprints.
Ms Ludford said both moves were being pushed through "without adequate exploration of either costs or their real contribution to security, and without robust testing of the claims of law enforcement agencies".
All telecoms "service providers" retain information already for business reasons, but different countries apply different rules on how long it can be kept - from just a few days to several months for some logged details.
Ireland, France, Britain, and Sweden are pushing for common standards of data retention specifically to help tighten the net on organised crime, drug smugglers and terrorists.