Fast boats and fast women have been the ruin of many a poor boy. But they can also prove a triumphant mix, as the wartime exploits of the Royal Navy’s 15th Motor Gun Boat Flotilla, described in Tim Spicer’s highly enjoyable book, show. An under-cover unit run during the second world war by the Secret Intelligence Service, it used sleek 110ft motor launches to ferry agents and supplies between England and France.