Whistleblower Edward Snowden tells his story in trailer for documentary ‘Citizenfour’ – watch

Snowden warns: 'Every site you visit is in the hands of a system whose reach is unlimited'

Whistleblower Edward Snowden tells his side of the story in a new documentary from Oscar-nominated filmmaker Laura Poitras

In the trailer Snowden warns: “Every border you cross, every purchase you make, every call you dial, every cell phone tower you pass, friend you keep, site you visit and subject line you type is in the hands of a system whose reach is unlimited but whose safeguards are not.”

Snowden, a former intelligence analyst, released thousands of classified documents in the biggest breach of the security of American secrets since Daniel Ellsberg’s leaking of the Pentagon Papers during the Vietnam War. He is on the run having been granted temporary asylum in Russia. He faces a potential 30-year prison sentence if he returns to the US.

In January 2013, filmmaker Laura Poitras received encrypted emails from the alias ‘citizen four’ who was ready to blow the whistle on the massive covert surveillance programmes run by the NSA and other intelligence agencies.

In June that year she flew to Hong Kong with reporter Glenn Greenwald for the first of many filmed meetings with the man who turned out to be Edward Snowden.

London Film Festival director Clare Stewart has called Citizenfour a “bitingly relevant film that speaks to the political consciousness of our times”.

As reported, Joseph Gordon-Levitt is in talks to play Snowden in Oliver Stone’s film The Snowden Files based on the book by Guardian journalist Luke Harding.

Poitras was nominated for an Oscar for her 2006 documentary My Country, My Country. Her new film is produced by Steven Soderbergh.

Citizenfour makes its UK debut at the London Film Festival on October 17 and will go on general release October 31. Watch the trailer below.