John le Carre 
The Mission Song 

»Mesmerising» Sunday Times
As an interpreter of African languages, Bruno Salvador is much in demand. He makes it a principle to remain neutral – no matter what he hears. But when he is summoned on a secret job for British Intelligence, he is told he will have to get his hands dirty. His mission is to help bring democracy to the Congo – democracy that will be delivered at the end of a gun barrel.
The Mission Song is an excoriating depiction of a corrupt world where loyalty can be bought and war is simply an opportunity to settle old scores.
»Simply astonishing … a formidably sophisticated work of fiction» Charles Cumming