I shan't say much (as I know at least a couple of people on m'flist will be wanting to read it), other than the title quote, which I can't resist, and that I spent the entire time alternating between shouting "Horowitz, you horrible, horrible man!" then cackling insanely at the end of chapters, and going "Oh, Alex!" at regular intervals.
Also, this bit cracked me up immensely:
(Alan Blunt is musing on the Rider family) - "John Rider had been a much more effective agent than his younger brother Ian." What, you mean he didn't have Ian's penchant for personalised numberplates? *cracks up*
Also, later on: "Ian had been mugged in Rome, involved in a car crash in Geneva, and had broken his arm skiing in Vancouver." I like to imagine that this had nothing to do with espionage, just that he was shit. XD