More than 500 of the world's leading authors, including five Nobel prize winners, have condemned the scale of state surveillance revealed by the whistleblower Edward Snowden and warned that spy agencies are undermining democracy and must be curbed by a new international charter.
The signatories, who come from 81 different countries and include Margaret Atwood, Don DeLillo, Orhan Pamuk, Günter Grass and Arundhati Roy, say the capacity of intelligence agencies to spy on millions of people's digital communications is turning everyone into potential suspects, with worrying implications for the way societies work.
They have urged the United Nations to create an international bill of digital rights that would enshrine the protection of civil rights in the internet age.
Their call comes a day after the heads of the world's leading technology companies demanded sweeping changes to surveillance laws to help preserve the public's trust in the internet – reflecting the growing global momentum for a proper review of mass snooping capabilities in countries such as the US and UK, which have been the pioneers in the field.
The open letter to the US president, Barack Obama, from firms including Apple, Google, Microsoft and Facebook, will be followed by the petition, which has drawn together a remarkable list of the world's most respected and widely-read authors, who have accused states of systematically abusing their powers by conducting intrusive mass surveillance.
It also includes JM Coetzee, Yann Martel, Ariel Dorfman, Amit Chaudhuri, Roddy Doyle, Amos Oz, David Grossman, and the Russian Mikhail Shishkin.
Henning Mankell, Lionel Shriver, Hanif Kureishi and the antipodean writers CK Stead, Thomas Keneally and Anna Funder are other globally renowned signatories.
The Guardian has published a series of stories about the mass surveillance techniques of GCHQ and its US counterpart, the NSA, over the past six months; two of the most significant programmes uncovered in the Snowden files were Prism, run by the NSA, and Tempora, which was set up by GCHQ. Between them, they allow the agencies to harvest, store and analyse data about millions of phone calls, emails and search-engine queries.
Though Tuesday's statement does not mention these programmes by name, it says the extent of surveillance revealed by Snowden has challenged and undermined the right of all humans to "remain unobserved and unmolested" in their thoughts, personal environments and communications. "This fundamental human right has been rendered null and void through abuse of technological developments by states and corporations for mass surveillance purposes, " the statement adds.
"A person under surveillance is no longer free; a society under surveillance is no longer a democracy. To maintain any validity, our democratic rights must apply in virtual as in real space."
Demanding the right "for all people to determine to what extent their personal data may be legally collected, stored and processed", the writers call for a digital rights convention that states will sign up to and adhere to. "Surveillance is theft. This data is not public property, it belongs to us. When it is used to predict our behaviour, we are robbed of something else – the principle of free will crucial to democratic liberty."