The European Court of Justice (ECJ) has ruled that data retention in Germany is not compatible with EU law, stating that internet and phone service providers should not store citizens' communications data without cause.

The case was triggered after Deutsche Telekom unit Telekom Deutschland and internet service provider SpaceNet AG challenged Germany’s data retention law, arguing it breached EU rules. The German court subsequently sought the advice of the EU court, which said that indiscriminate data retention should only be applied in exceptional circumstances. 

“The Court of Justice confirms that EU law precludes the general and indiscriminate retention of traffic and location data, except in the case of a serious threat to national security,” the judges said.

“However, in order to combat serious crime, the member states may, in strict compliance with the principle of proportionality, provide for, inter alia, the targeted or expedited retention of...