Answering an advertisement in the London Times newspaper, David Lomax - former military pilot and now a part-time antique dealer with a stall down the Portobello Road - finds himself caught up in a bizarre and deadly adventure involving a trailer-load of valuable racehorses, the ruthless Basque separatist movement ETA, a shadowy entrepreneur named Smith, a terrified young Spanish widow - and twelve million dollars of someone's money. After a desperate chase across Spain, David comes face-to-face with his single-minded pursuers in Gibraltar. Here he negotiates for his life in a poker-like mind game played out deep inside the secret tunnels. The 'choke point' of the title is the Rock itself, the most southerly point of Europe where millions of migrating birds gather before continuing their journey to Africa, and where predatory falcons reap a bloody harvest - a chilling parallel in the story to the activities of ETA and its sinister connections.