But while the philosophy of Beirut is lacking, the film is generally entertaining.

Tony Gilroy's script is intricate and intelligent, with an appropriately cynical view of US foreign relations. And Hamm makes hay with his best role since Mad Men.

An enjoyably pacey spy picture, unfolding against the backdrop of a country that has imploded.

Responsible for penning the likes of Michael Clayton and the Matt Damon Bourne series, writer Tony Gilroy adds more intrigue to his resume with this tense drama.