There is a lot to be said for the fact that I found this review difficult to write. There is no doubt that the performances, cinematography, and casting was exceptional. There’s a particularly enjoyable (or, more precisely, familiar) and inimitable Britishness throughout. That is easy, I could write about that happily.

It is the subject matter that is difficult. A deeply moral quandary about a sacrifice made to expose the truth for public knowledge. I feel as if I should be talking about it- that everyone should be talking about it. That is the impression I was left with. Official Secrets is an exceptional political thriller, at a time where all politics could classify as thriller-worthy. This is the true story of whistleblower Katharine Gun.

Katharine Gun is a 27-year-old junior analyst at GCHQ, working as a translator. Her life is seemingly normal (save for the fact that she is at the epicentre of British intelligence). She lives in Cheltenham with her husband, Yasser. It’s the early 2000s and Tony Blair is prime minister. There are various clips of Blair and Bush peppered throughout the film and the Iraqi war is high on everyone’s radar. It’s clear that there is strong opposition to war in Britain.

Katharine exposes a memo from the US National Security Agency enlisting the help of British intelligence to collect information on U.N. Security Council members to swing a crucial vote on the invasion of Iraq. In doing so, she breaches the Official Secrets Act.

The aftermath of this decisions is truly gripping, and Katharine’s personal and legal struggles are compelling told. To what extent is a job a job, removed from one’s own personal and moral sensibilities? How far should one go for the sake of public knowledge?

Katharine Gun (Kiera Knightley) and Ben Emmerson (Ralph Fiennes) are staggeringly portrayed, and there is a particular warmth to their character’s interaction in court. The film ends on a staggering note, and I leave the cinema to collect my thoughts- only to find that the questions raised go far beyond of an afternoon screening.

Official Secrets is in cinemas now.

Reviewed as Film of the Week, in partnership with Cameo Cinema, Edinburgh.