Without Laura Poitras, the meeting between Edward Snowden and Glenn Greenwald might never have taken place. When the whistleblower contacted Greenwald in 2011, the latter was reluctant to use secure encrypted communications. Snowden turned to Poitras, who was familiar with such techniques. It’s easy to see why. The US authorities had had their sights on the film-maker ever since she made the Oscar-nominated documentary “My Country, My Country” about the war in Iraq in 2006. Whenever she travels, her air ticket is marked SSSS, which stands for “Secondary Security Screening Selection”. This means she is on a watch list and is subjected to extensive questioning when she returns from abroad. She has been questioned more than 40 times and her computer equipment is regularly seized and inspected. She has never been given a reason for this harassment. Poitras now lives in Berlin where she continues her work with Greenwald on the surveillance practices of the NSA. She has received numerous honours and awards for her documentary work.