Just finished "Sweet Danger", by Margery Allingham; the 5th book in the "Campion" series. Campion is employed by the British government to try to find the ancient heirlooms which will prove the British Sovereignty of the tiny (and fictitious) Balkan state of "Averna", which has suddenly become important in world affairs due to a fortuitous earthquake suddenly providing the previously land-locked state with a coastline and a natural harbour (improbable plot-lines, anyone?
). Tremendous fun, and highly recommended.