John le Carré is enjoying a remarkable Indian summer. The Mission Song, his twentieth novel, takes us back to Africa – not the Kenya of The Constant Gardener, but the Congo of Conrad's Heart of Darkness, from which this book takes its epigraph. Bruno Salvador is hired as an interpreter at a secret conference of Eastern Congolese tribal warlords who are plotting to overthrow the Kinshasa government with the backing of Western financiers and with the connivance of British intelligence. The ostensible purpose of the coup is to restore democracy to the country. However, when Salvador eavesdrops on a secret conversation, he realises there are more sinister plans afoot. The syndicate wants to carve up Eastern Congo's mineral wealth: gold, oil, diamonds, and coltan. In a Machiavellian twist, it transpires that the Kinshasa government is in on the deal. It will turn a blind eye to any coup planned in return for a piece of the action – ‘the People's Portion’.

The Mission Song is a complex story of political chicanery where everybody is double-crossing everybody else. If, like me, you don't know your Mai Mai from your Banyamulenge, you might get lost in the minutiae of tribal politics; but that won’t