The court ruled that that while bulk surveillance can be justified to track terrorists and criminals and protect national security, the collection of data must indicate the types of crimes that would lead to bulk gathering of information, which classes of people would be subject to having their data gathered, and of course, procedures for how the data would be used, how it would be shared, and when it would be destroyed.
In their ruling, judges declared there was insufficient monitoring of what information was being collected and that some safeguards were "inadequate".
Brought before the European Court of Human Rights by Big Brother Watch, English PEN, and the Open Rights Group following the revelations by whistleblower Edward Snowden that the United Kingdom and other countries had been conducting secret population-scale communications interception against their citizens, the cases were joined together for a single hearing.
The ECHR decided the surveillance programme violates Article 8 of the European Convention on Human Rights-the right to a private life and a family life-due to what the court regarded as "insufficient oversight" of the selection of collected communications.
The UK's bulk interception of data came to light in 2013 as part of NSA whistleblower Edward Snowden's revelations about United States and UK intelligence operations.
The court crucially said bulk interception was legitimate and it had seen no evidence it had been abused. "It continued: "[the ruling] permits national governments a "wide margin of appreciation" in deciding whether to engage in bulk interception and greenlights vast intelligence sharing with the US National Security Agency (NSA)". These included indiscriminate "population-level" data collection, a lack of oversight in the collection process and the lack of safeguards to prevent the abuse of collected data.More news: Hurricane Florence weakens slightly as it moves toward USA coast: NHC
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They wrote: "In view of the potential chilling effect that any perceived interference with the confidentiality of journalists' communications and, in particular, their sources might have on the freedom of the press, the Court found that the bulk interception regime was also in violation of article 10".
It said: "The content of an electronic communication might be encrypted and, even if it were decrypted, might not reveal anything of note about the sender or recipient". "The government will give careful consideration to the court's findings", said a Home Office spokesperson.
"Our government has built a surveillance regime more extreme than that of any other democratic nation, abandoning the very rights and freedoms that terrorists want to attack".
Following the Snowden revelations, the rules were replaced in November 2016 by the Investigatory Powers Act, a new law that effectively puts mass surveillance powers on a statutory footing.
Civil liberties campaigners who brought the case hailed the judgment as a landmark victory against the mass surveillance that governments have defended as an important tool in fighting terrorism. Today, the Court has ruled the UK's surveillance illegal, despite arguments that the Regulation of Investigatory Powers Act 2000 (RIPA) and its replacement the Investigatory Powers Act 2016 (IPA) made it legal.
"We will push on with our High Court challenge against the Investigatory Powers Act and I'm sure we'll draw on the judgement of today to explain why it means that act is also unlawful", she added.