CIVIL liberty campaigners have heralded a “watershed moment” for privacy as they challenge UK surveillance laws in court.

Amnesty International and Liberty are amongst groups taking a case against the legislation to the European Court of Human Rights today.

Organisations from Egypt, Canada, Hungary and Ireland are also amongst those involved.

The move is the latest stage in a long-running effort to challenge the government’s ability to gather data on citizens following revelations by US whistleblower Edward Snowden in 2013.

Snowden revealed how UK intelligence agency GCHQ was intercepting and processing private communications and sharing data with America’s National Security Agency. Information was also shared with parties from other nations.

Three years ago the Investigatory Powers Tribunal – the UK court with jurisdiction over GCHQ, MI5 and MI6 – ruled that these practices may in principle comply with the UK’s human rights obligations, a finding that is the subject of the European challenge.

Complainers say British surveillance laws and practices affect the privacy and other rights of millions of citizens around the world, partly because major internet cables run to and from UK territory.

They have also highlighted concerns about risks to confidentiality and the work of human-rights groups.

The case is also expected to have wide-ranging implications for the Investigatory Powers Act which was passed last year, changing the legal framework governing surveillance matters and allowing for further blanket surveillance.

In addition to the indiscriminate interception of communications, the legislation – which the government says will aid the fight against terrorism and organised crime – allows the security agencies to hack computers and other electronic devices on a large scale, harvesting “potentially huge” amounts of personal data from individuals who are not suspected of any criminal behaviour.

Nick Williams, Amnesty International’s senior legal counsel, said: “This case is a watershed moment for people’s privacy and freedom of expression across the world. The case concerns the UK, but its significance is global.”

Liberty director Martha Spurrier added: “Our organisations exist to stand up for people and challenge abuse of power. We work with whistleblowers, victims, lawyers, journalists and campaigners around the world, so confidentiality and protection of our sources is vital. The UK Government’s vast, cross-border mass surveillance regime – which lets it access millions of people’s communications every day – has made those protections meaningless.

“Losing our privacy is the gateway to losing everything that keeps us free – the right to protest, to a fair trial, to practise our religion, to think and speak freely. No country that deploys industrial-scale state surveillance has ever remained a rights-respecting democracy.”