Official Secrets – one whistleblower’s failed attempt to stop the Iraq war (in cinemas from Friday 18 October)

Keira Knightly starts in the true story of Katharine Gun, a GCHQ staffer who in January 2003 leaked an NSA memo requesting UK help for intelligence that would put the smaller, non-permanent members of the UN Security Council under pressure to vote for a resolution that would allow the invasion of Iraq. Arrested in March, and charged under Section 1 of the Official Secrets Act in November, the prosecution declined to offer evidence when her case came to court in February 2004.

“Just because you’re the prime minister doesn’t mean you get to make up your own facts,” says Gun early on in Official Secrets, a sober film directed by Gavin Hood which makes little attempt to glamorise or hype up the account of a failed attempt to stop a war. Gun is clear that “I work for the British people. I do not gather intelligence so the government can lie to the British people.”

With a performance that carries much of the film, Knightly holds such emotion in her face as her character lives through the consequences of her action on her own freedom and her that of her husband (Yasar played by Adam Bakri) whose immigration status is under threat. Despite the huge cast around the central figure of Gun, the co-workers, journalists, lawyers and intelligence sources are well-defined, and introduced very naturally and without fuss into the 112-minute narrative.

Matt Smith plays The Observer journalist (Martin Bright) who eventually published a story about the leak once its veracity had been stood up. Conleth Hill captures the cautious yet hungry for a story approach of editor Roger Alton, while Rhys Ifans is more than flamboyant as the paper’s US correspondent Ed Vulliamy.

Ralph Fiennes picks up the role of Ben Emmerson, the QC who worked with Liberty to defend Gun. The collapsing relationship between Emmerson and his friend and former colleague who had become Director of Public Prosecutions Ken Macdonald (played by Jeremy Northam) is well crafted. Though this major tiff begs a question that surrounds much of the film: how much of it is true, and which aspects are fictionalised?

As the story of one person taking on the establishment and calling out disinformation and propaganda – in this case the false claims being made by figures like Tony Blair and Colin Powell to justify a war in Iraq – chimes with modern worries about the reckless abandonment of truthfulness at the top of some western governments.

The story is thankfully procedural rather than having been written as a political thriller. The rush through traffic to the Harmondsworth Immigration Removal Centre in some ways adds unnecessary drama to a film that is more about telling the story of a brave civil servant than providing thrills and spills. Watch out for the nostalgic use of a Zip drive!

Official Secrets will do well on the small screen. There’s little in the production that absolutely demands a cinematic experience. However, the uninterrupted nature of a couple of hours in the picture house gives time for alarm bells to ring and left me wondering what pushes someone over the edge to become a whistleblower, particularly having recently finished reading Edward Snowden’s memoire Permanent Record and the leak that might yet precipitate an impeachment hearing for President Trump.

You can find Official Secrets in most local cinemas in UK and Ireland from Friday 18 October.