Meanwhile, one of my pet peeves is that while they stop small sharp items, I can, and do, carry my 1.2 meter umbrella with a solid wood handle and thick steel ribs. It would take about 10 minutes to reshape it into a sturdy pike. To be clear, I don't think they should stop them, but I do think that if you aim to stop sharp items with the excuse that they might be used as weapons, stopping something that can actually easily be turned into a fairly dangerous weapons ought to be top of the list.

First time I was travelling with it, I went to check it in, and they looked at me as if I was stupid. Clearly no terrorist has tried to use a huge umbrella as a pike yet, so it's not yet a risk. If I was a terrorist, testing a suitable set of objects with enough sharpened metal pieces for whether or not they'd ask me to check them in would be trivial - any terrorists being stopped by their lack of ability to bring something sharp on are so dumb they'd be stopped by someone drawing a stop sign in crayons and insisting they're not allowed to pass.

So the terrorists are either really stupid, there aren't that many of them, or they, like you, are smart enough to realise that they'd better have some pretty horrible weapons to be able to survive a hijack attempt in a post-9/11 world.

In other words, it's not even about stopping sharp items, but about giving the appearance of stopping a suitable set of objects that will keep people concerned about terror threats.

What about liquids? Pretty much every trip I end up forgetting some bottle or other of liquids, generally a half litre bottler of some drink, often because the mother of my child keeps putting bottles in his bag that I don't notice until after security. Not once have they been noticed at the security checks.

So it's a show, as those who do want to get liquids past can just put them in their carry on and send it through with good odds of being able to walk straight on. If they cared, they'd do better. But they don't care, as this is not about stopping a viable plot, but about keeping up appearances.

Meanwhile my 4 year old was picked out for secondary screening when we flew to visit my mother for christmas, without setting off the metal detectors, and had to pass his shoes through and go through the new scanners, and get patted down; I was furious, but didn't want to upset or scare him or risk messing up his christmas by making a fuss about it; and when we'd gone through, I found a full drinks bottle in his bag that they'd missed.