Mr Tao, the 2007 laureate of WAN-IFRA’s Golden Pen of Freedom award, was sentenced to 10 years in prison in 2004, accused of leaking state secrets abroad, after Yahoo China aided Chinese authorities in identifying him. His release was announced by the Independent Chinese Pen Centre.

“While we are delighted that Shi Tao is free, his imprisonment by Chinese authorities signaled a warning to others that anyone who criticised authorities could be jailed. Shi Tao should never have been jailed in the first place,” said WAN-IFRA CEO Vincent Peyrègne.

“The actions of Yahoo China -- releasing his private details to the authorities -- were questionable, and illustrated the fact that journalists in many countries face new surveillance issues in the digital age.”

The Golden Pen of Freedom is an annual award made by WAN-IFRA to recognise an outstanding action in the cause of press freedom.  Mr Tao was awarded the prize in 2007 after exposing government instructions to the media on how the journalists must cover the 15th anniversary of the Tiananmen Square massacre.

Shi Tao was already in prison when the award was presented. His mother, Gao Qinsheng, accepted on his behalf. Speaking at the 60th World Newspaper Congress in Cape Town, South Africa, Gao Qinsheng said: “I feel deeply honoured for my son to be receiving this honour. Shi Tao is a professional journalist but also a direct victim of the shackles of press freedom. He received the heavy sentence of 10 years imprisonment because he published what the authorities considered should not be made public “.

During its meeting in Bangkok, Thailand, on 2 June 2013 at the 65th World Newspaper Congress and 20th World Editors Forum, WAN-IFRA had called for the release of Shi Tao and further called on the Chinese government to free all imprisoned journalists and put an end to its attacks on freedom of expression.

The global organisation of the world’s newspapers and news publishers called on China to reverse its persistent battle to stifle the Internet and encouraged the authorities to instead welcome a more open and participatory information age.

However, over the past months, WAN-IFRA has become increasingly concerned that the digital age has brought with it greater surveillance of journalists and others, not just in China, but also in established democracies.

“The surveillance of journalists in our digital age is a threat to press freedom and the confidentiality of sources not just in China, but in democratic countries as well. It is extremely troubling when developed democracies do not live up to their own standards, and provide repressive regimes with bad examples that are used to justified their own behaviour,” said Mr Peyrègne.

“In recent months, authorities in the United States monitored telephone calls of journalists at The Associated Press. In the United Kingdom, authorities ordered the destruction of computer drives belonging to the Guardian that held information relating to the Snowden files. In Switzerland, a journalist’s computer was seized after he revealed suspected plagiarism at a university. And today, we have heard that journalists at Le Monde in France had their phone conversations recorded by police for a month on the order of a judge, relating to a kidnapping case.

“Shi Tao’s release is a reminder that journalists’ sources must be protected, so that the press can perform its function in encouraging open debate and free societies.  We call on China and all countries to release journalists held in prison because of their writings,” Mr Peyrègne said. "We also call on governments to respect the right of journalists to protect their sources, a concept that is in the best interests of society as a whole."