­The coppers are doing VIP protection training in the grounds of my workplace. We were warned a couple of times in advance, but the occasional boom of a controlled explosion thumping through the office, followed by small arms fire, has still proved faintly unnerving. I have a light but persistent hangover today, and am wondering whether I could get away with taking shelter under the desk and surreptitiously going to sleep.

The explosions have also reminded me of the ever-present threat of war and destruction, so I have taken the opportunity to refresh my apocalypse drills by skimming through the Protect and Survive pamphlet that I keep in my in-tray.

A while back, E and I had a little Sunday trip to Kelvedon Hatch nuclear bunker in Essex (famous for its road sign), and for a nominal sum I picked up a copy of the government’s guidance on what to do in the event of a nuclear attack. It was designed to be distributed free to every household, and was made generally available in 1980. It contains helpful, vintage advice on the various phases and hazards of a nuclear bomb going off, survival preparation, how to build a (decidedly flimsy) apocalypse shelter, what to do about poo, and various grim details to do with disposing of casualties. The general idea seems to be to hide somewhere with some tins and listen to the radio.

To the untrained eye, the picture below might appear to be a den of the sort that a small child would build under the stairs. In fact, should you ever hear the warning sirens, here is how to prepare an impenetrable bomb room.