Official Secrets review – powerful political thriller

Early in the political drama Official Secrets, Keira Knightley’s real-life whistleblower Katharine Gun watches Tony Blair on television, giving his now infamous justification for the impending Iraq War, namely the existence of weapons

There’s simply no escaping the resonance. The current occupant of No 10 isn’t the first to be economical with the truth; the real shock is that we keep on putting up with it. And the power of the film resides in the fact that the idealistic, courageous Katharine Gun would not. 

The film opens with Gun about to face trial for breaching the Official Secrets Act – Knightley’s face expressing the sheer terror of someone in that position – before winding back a year to explain how she got there. 

Katharine is working as a Mandarin translator at the intelligence agency GCHQ, in Cheltenham. One day she and her colleagues receive a classified email from America’s National Security Agency, requesting that the Brits spy on delegates from the UN’s security council, with a view to blackmailing them to vote for the resolution in favour of war, whose chief proponents are President Bush and Tony Blair. In the UK the very idea of the war is historically unpopular with the public – and here’s evidence of its illegality. Katharine secretly copies the memo and smuggles it out of GCHQ to a friend who is an anti-war activist, through whom it reaches Observer journalist Martin Bright (Matt Smith, pictured above right with Matthew Goode). 

Until now the film has been operating on something of a whisper. Once Smith appears on screen – quickly followed by the equally energetic (nay combustible) Rhys Ifans as fellow journalist Ed Vuillamy – there’s a sonic boom. Hereon, the action switches urgently between the paper’s investigation of the memo’s authenticity and Katharine’s personal hell as the leak is revealed, which includes the threat of deportation for her Muslim husband Yasar (Adam Bakri).

Gavin Hood is an intriguing director, alternating between mainstream fare (X-Men Wolverine, kids’ sci-fi Ender’s Game) and issues-based dramas charting government malfeasance, such as rendition (Rendition) and the use of drone strikes (Eye in the Sky). He’s on strong form here, with a film that’s gripping, righteous, relevant, moving – in short, a very, very good yarn that just happens to be true. 

At the heart of it is Knightley, impressively commanding as a woman who is principled and defiant, but also deeply vulnerable as the government cranks up its intimidation. Around his star Hood has assembled a comprehensively fine cast, with a particularly lovely turn by Ralph Fiennes as the lawyer determined to defend Gun against the odds. 

• Read more film reviews on theartsdesk