Re the post before mine: One of the nightmares of any security organisation is competent – really competent – terrorists. There was a mass-market book, for example, that I recently read that had as a central plot the detonation of a large nuke by a terrorist organisation. Ho hum, you say, isn’t that original? Except that this particular one had an extremely large force multiplier built in; the bomb was to be detonated on Cumbre Vieja, thus causing devastation of global (or at least hemispheric) scale from one nuke.

On a slightly smaller scale, there are many tunnels and aqueducts in various major cities where a relatively small charge could cause an awful lot of damage, running probably into billions of dollars and hundreds of lives. There are all sorts of possibilities, and some of them probably haven’t been thought of yet. (Incidentally, the 9/11 atrocity was anticipated in fiction by 7 years, by Tom Clancy – not exactly an inconspicuous figure.)

Perhaps the various security organisations should have an assortment of thriller and SF writers on retainer, to dream up scenarios that they can then defend against? Some of them might even be patriotic enough not to spill the beans.