The EU's top court on Tuesday put limits on how European spy and security agencies could harvest troves of personal data, but said this could be done under a serious threat to national security.
At the request of the courts in Belgium, Britain, France, and the European Court of Justice confirmed that "EU law precludes national legislation" that requires telcos and tech companies to carry out the "indiscriminate retention" of data, a statement said
However, it does allow for exemptions in cases of "serious threat to national security" or the "fight against serious crime", under the supervision of a judge or an independent administrative authority.
This lifting of the ban would have to be "limited in time to what is strictly necessary," the court added.
The decision will be closely looked at by privacy activists who fear wide loopholes that would allow unfettered data spying by state agencies.
The legal onslaught began after revelations by Edward Snowden of mass digital spying by US agencies that also revealed cooperation with Washington by the UK's spy agencies.
The mass harvesting of data is a central part of anti-terror laws passed in several Western countries in the wake of September 11 and other attacks.
OnePlus 8T leaked specs look great but where is the cheaper Nord? We discussed this on Orbital, our weekly technology podcast, which you can subscribe to via Apple Podcasts, Google Podcasts, or RSS, download the episode, or just hit the play button below.