Our Kind of Traitor book by John Le Carre

In the wake of the collapse of Lehmann Brothers and with Britain on the brink of economic ruin, a young English couple takes a tennis vacation in Antigua. There they meet Dima, a Russian who styles himself the world's number one money launderer, who wants, among other things, a game of tennis. Back in London, the couple is subjected to an all-night interrogation by the British Secret Service, which also needs their help. Their acquiescence will lead them on a precarious journey through Paris to a safe house in Switzerland, helpless pawns in a game of nations that reveals the unholy alliances between the Russian mafia, the City of London, the government and the competing factions of the British Secret Service.