Germany's top court curtailed a law on Wednesday requiring telecom firms to store phone and Internet data for six months, dealing a new blow to the government's efforts to beef up anti-terrorism measures.
Opposition politicians, civil liberties campaigners and many citizens had opposed the law, a divisive issue in a country haunted by memories of domestic spying by Hitler's Gestapo and communist East Germany's Stasi secret police.
A reaction to bomb attacks in Madrid and London in the last few years, the law obliges telecom firms to keep a record of who contacted whom, and the time and location of calls.
The Federal Constitutional Court ruled data may be stored, but details may only be transferred to investigators in the event of inquiries into serious crime.
The decision was the latest in a series of rulings against tighter security measures introduced by Chancellor Angela Merkel and previous governments, and it drew praise from civil liberties campaigners who want greater data protection and privacy rights.
"The grand coalition (of Merkel's Christian Democrats and Social Democrats) should finally draw the lesson of these verdicts and stop crossing the limits of constitutionality on citizen rights," said Claudia Roth from the Green Party.
Joerg van Essen from the opposition FDP called on the government to "finally turn its back on ever-increasing preventive policies and turn towards an interior and legal policy conscious of basic rights."
In 2004, judges ordered the government to tighten rules for bugging homes. Two years later, the court threw out a law meant to prevent mass casualties in potential Sept. 11-style attacks by allowing the shooting down of hijacked planes.
In 2006, the court also set strict limits on the ability of police to trawl electronic databases at random in search of possible terrorists. It said general data trawling was only lawful if there was a concrete threat to Germany or one of its regions, or a danger to human life or freedom.
The court said earlier this year domestic security services were allowed to monitor computers of suspected criminals, but only if they had evidence showing they were dangerous.
Separately, the judges also said police were no longer allowed to register large numbers of car number plates at random and compare them with records. The measure must be restricted to concrete threats or to areas with high crime rates.
