Keira Knightley as “Katharine Gun” in Gavin Hood’s Official Secrets. Courtesy of IFC Films. An IFC Films Release.

Keira Knightley as “Katharine Gun” in Gavin Hood’s Official Secrets. Courtesy of IFC Films. An IFC Films Release.

REVIEW: “Official Secrets” ★★★★

Powered by an all-star cast and an incredible story inspired by true events, “Official Secrets” is utterly enthralling stuff, especially if you enjoy political and legal dramas.

“Official Secrets” is the kind of spy thriller we’re not used to seeing, but we should see more of.

Based on true events, it presents international espionage in a grounded, unglamorous way. More importantly, it presents how electronic espionage can be used to influence the course of 21st Century world events.

Powered by an all-star cast and an incredible story inspired by true events, it’s utterly enthralling stuff, especially if you enjoy political and legal dramas.

What’s it about?

“Official Secrets” tells the story of whistleblower Katharine Gun. In 2004, Gun was accused of a crime under the United Kingdom’s Official Secrets Act of 1989.

A year before, Gun worked as a translator for a British Intelligence agency. Her everyday work involved obtaining information electronically to help her government conduct international relations. But one day she and her entire department received a memo that shook her to her core.

The memo contained a directive from the American NSA, approved and passed along by the British government, for an operation targeting members of the United Nations Security Council from five nations. The goal was simple: find something potentially incriminating or embarrassing to those members so that they could be strong-armed into voting for a new UN resolution authorizing the use of force against Saddam Hussein and Iraq.

Sickened by the directive and its implications, Gun feels she must do something to try to prevent an unjust and immoral war. Her eventual choice leads to the memo being published by a British newspaper, The Observer, and her coming forward about her actions to authorities.

Gun’s actions didn’t stop the invasion of Iraq, of course. What they did do was get her in a lot of legal trouble. She’d confessed to committing a crime. While her intent was to save lives, she’d violated her oath regarding the handling of classified information.

Was a she a patriot, or a criminal? The question was set to be debated during her trial, and then … Well, you’ll just have to see for yourself what happened next.

Official Secrets movie poster

Enthralling whistleblower drama

Inspired by the novel “The Spy Who Tried to Stop a War” by Marcia and Thomas Mitchell, “Official Secrets” certainly feels dramatized. However, that doesn’t mean it doesn’t feel authentic.

Director Gavin Hood (“Ender’s Game“) keeps things grounded here. This is a quiet, understated film, filled with people speaking in code, speaking in tense, sometimes terse whispers.

No explosions. No clocks ticking and assassins peering at targets through scopes. Hood uses very few of the typical espionage film tropes here.

Yet Hood still delivers a gripping thriller with a resolution that should come as a surprise. (Unless you know how it turned out in real life, of course.)

The writing and structure of the film, while conventional, is satisfyingly effective. You may have a sense of what’s coming next at certain points, but that knowledge takes nothing away from emotional impact once things play out.

RELATED: See also our review of “Colette,” starring Keira Knightley

Worth seeing?

And we haven’t even talked about the cast of “Official Secrets” yet.

Knightley leads a veritable whos-who of British stars here, including Matt Smith (“Doctor Who“), Ralph Fiennes (“The White Crow“), Rhys Ifans (“The Amazing Spider-Man“) and more. Keen-eyed “Game of Thrones” fans should be able to pick out a few of their favorites in smaller but important roles here, as well.

Knightley is superb in her turn as Gun. She projects palpable passion and raw emotion into her take on the character but never pushes her in a direction where she becomes larger than life.

The key here is that Gun was just an ordinary person. Yes, she had an extraordinary job, but the moral choices she makes are portrayed in a way that’s meant to prompt the “What would you do?” conversation.

Her work alone in “Official Secrets” makes the film worth seeing. But the entire cast delivers fine work in telling an incredible story that just happens to be true.

Official Secrets

Starring Keira Knightley, Matt Smith, Adam Bakri, Matthew Goode, John Heffernan, Ralph Fiennes, Indira Varma, Rhys Ifans, Conleth Hill, Tamsin Greig, Kenneth Cranham, Myanna Buring, Katherine Kelly, Shaun Dooley, and Jeremy Northam. Directed by Gavin Hood.

Running time: 112 minutes

Rated R for language.