Salmon like cold places where it rains a lot. Yemen is neither cold nor particularly rained-upon. Introducing salmon fishing to Yemen, therefore, is patently insane.
Dr Fred Jones, fisheries-scientist hero of the film Salmon Fishing in the Yemen, is trying to explain this to his boss. "Did you get my email?" he asks. "Yes," his boss replies. "What did it say?"
The project has been dreamed up by a Yemeni sheikh with a penchant for wading into Scottish rivers, fully robed, for a spot of fishing. "If your sheikh wants to pour his money down the drain, why doesn't he buy himself a football club?" Fred (Ewan McGregor) asks Harriet Chetwode-Talbot (Emily Blunt), His Excellency's representative in London.
The sheikh's plan to wade in a wadi is being backed by the British government, which needs a Middle Eastern good news story after marines accidentally blow up an Afghan mosque.
Fred's Damascene (or possibly Adenite) conversion comes after he visits the sheikh's Scottish estate to talk about fish and faith. Besides, His Excellency is handy with a rod and fly. And so Fred, Harriet and the sheikh head off to Yemen together.
What follows is a gentle romantic comedy, but an irresistibly engaging one. Fred's marriage makes his relationship with his boss appear a communication exemplar. Harriet's soldier boyfriend, meanwhile, is reported missing in action midway through the project. Fred, therefore, turns around and battles through crowds to comfort her: the human version of swimming upstream.
The script, written by The Full Monty's Simon Beaufoy, sparkles throughout. More to the point, it sparkles in noticeably different ways depending on who is speaking.
It is true that the sheikh is a bit of an Eastern cliche, spouting cod (to mix fishy metaphors) spirituality and mysticism. And it is similarly true that the villains of the piece are evil A-rabs who dislike change and modernity. But on the whole, its characters are beautifully, roundly drawn.
At a key point in the film, a single salmon leaps out of the water and up a waterfall. It is a gesture suffused with joyousness and optimism. Salmon Fishing in the Yemen is the cinematic equivalent of that leap.
Salmon Fishing in the Yemen is in cinemas now.