European court rules that governments can only retain data on a targeted basis - Photo credit: PA Images 

In response to a case brought initially by Labour deputy leader Tom Watson and Conservative MP David Davis, the European Court of Justice said that governments should only use targeted – not indiscriminate – retention of data to combat serious crime.

The pair – who were challenging the legality of the UK government’s surveillance agency GCHQ’s bulk interception of email and electronic communications data – had already won a case in the high court but an appeal by the government sent it to the EU’s highest court.

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The ruling, which says that EU law overrules national legislation will be a blow to the government’s Investigatory Powers Bill, which passed into law last month, as it could open it up to challenges. However, it is not clear what the long-term effect will be after the UK leaves the European Union.

The ECJ ruling says that EU law “precludes a general and indiscriminate retention of traffic data and location data”.

It is up to member states to make provisions for targeted retention of data, it said, but this must be “solely for the purpose of fighting serious crime” and must be “limited to what is strictly necessary”.

The ECJ noted that the retained data was “liable to allow very precise conclusions to be drawn concerning the private lives of the persons whose data has been retained”.

It added: “The fact that the data is retained without the users of electronic communications services being informed of the fact is likely to cause the persons concerned to feel that their private lives are the subject of constant surveillance.

“Consequently, only the objective of fighting serious crime is capable of justifying such interference.”

In addition, government access to the retained data “should, except in cases of urgency, be subject to prior review” by an independent authority and that the data must be stored within the EU.

Davis, who is now Brexit secretary, withdrew from the case when he was appointed to his new role.