The movie follows a GCHQ linguist who discovers a top-secret National Security Agency (NSA) memo in the lead up to the Iraq war – and it’s fair to say it’s a hit with viewers
Tom Towers Senior News Reporter
11:39, 24 Nov 2025
The film tells the tale of Katharine Gun (Keira Knightley), a GCHQ linguist who stumbles upon a top-secret National Security Agency (NSA) memo(Image: IFC Films/rottentomatoes)
A “jaw dropping” and “remarkable” spy thriller based on an unbelievable true story is set to air on BBC tonight.
Based on real events in the lead-up to the Iraq War, Official Secrets tells the tale of Katharine Gun (Keira Knightley), a GCHQ linguist who stumbles upon a top-secret National Security Agency (NSA) memo outlining a covert plan – the US and UK were gathering compromising intelligence on UN Security Council diplomats to blackmail them into supporting the war.
Knightley gives a “mind blowing” performance as Gun, whose moral compass spins out of control when she realises just how deep the deception goes. Ralph Fiennes plays Ben Emmerson, the experienced human-rights barrister who steps in to defend Gun.
Martin Bright, the Observer reporter who helps bring Gun’s revelation to public light, is brought to life by Matt Smith.
She discovered the U.S. and U.K. were gathering compromising intelligence on UN Security Council diplomats(Image: IFC Films/rottentomatoes)
Directed by Gavin Hood, the movie is adapted from the book The Spy Who Tried to Stop a War by Marcia and Thomas Mitchell. Hood didn’t just rely on second-hand sources: he spent five full days talking face-to-face with the real Katharine Gun, plus lengthy conversations with journalists and her lawyer, gathering testimony that wasn’t all in the book.
Unlike glossier spy-thrillers, the film favours dim office corridors, quiet interrogation rooms and the hum of photocopiers, giving the drama a claustrophobic, realistic feel. In terms of faithfulness to real life, the movie leans surprisingly close to the truth — though, as Hood admits, some compression was inevitable.
Some scenes are fictionalised for emotional clarity – like Gun reacting audibly in the office to the memo, and much of the courtroom tension is streamlined. That said, many of the film’s key moments are rooted in reality — including a scene involving a spell-check gaffe that helped discredit (and then vindicate) the memo.
Ralph Fiennes plays Ben Emmerson, the experienced human-rights barrister who steps in to defend Gun(Image: IFC Films/rottentomatoes)
On Rotten Tomatoes, where the film holds an 82% approval rating, one fan describes it “as one of the most underrated movies of the last decade”. Another called it “well cast” and a “jaw dropping story”.
A third wrote: “A taut well-acted thriller, that marks a horrible time in history. It’s a remarkable and moving story of courage about doing what’s right on the grandest scale there is.” Critics also praised the balance Official Secrets struck between emotional drama and political urgency. The Guardian called the film “nuclear-level office politics” and highlights Knightley’s “focused, plausible and sympathetic” performance.
While preparing for the role, Knightley was taken aback at the impact of the anti-war protests held across the world.
She told TIME: “When you read those emails, you realize that actually it did have an effect, and if as a public we had stayed out on the streets, and if we had continued to protest, then maybe — and I don’t know this for sure, but maybe — there would have been a very different history.
“And that’s, in one way, kind of a great tragedy, but it also filled me with hope.”
Official Secrets will air at 11pm on BBC2 tonight (November 24).
