In January 2013, filmmaker Laura Poitras was several years into the making of a film about abuses of national security in post-9/11 America when she started receiving encrypted emails from someone identifying himself as "citizenfour". In June 2013, she and reporter Glenn Greenwald flew to Hong Kong for the first of many meetings with the man who turned out to be Edward Snowden. She brought her camera with her. The film that resulted from this series of tense encounters is a unique document in the history of cinema, capturing a staggering act of bravery on the part of both filmmaker and subject.

After a preview screening at the ICA in London we were joined by Jen Robinson (Director of Legal Advocacy at The Bertha Foundation), Eric King (Privacy International) and Jimmy Wales (founder of Wikipedia).