We have already seen how - somewhere deep in my childhood - I developed an obsession with the Post Office Tower - or rather, as I discovered - Post Office Towers.

I also liked encyclopedias of various types and was always disappointed that you couldn't take them out of the library. I had to make do with the ones I received for Christmas or birthday, but a lot of the time that was enough for me. Many was the evening I would spend poring over The Wonder Book of Do You Know or The Guinness Book of Records.

And it was thanks to this that I discovered that there were other towers in the world, some of them taller than the Post Office Tower. At first this made me feel irritated and inferior - I felt proprietorial about the tower I saw on a regular basis and the criticism implicit in the fact that the Eiffel Tower and the Empire State Building were taller upset me. But then I began to obsess about these towers themselves, drawing pictures of them, building replicas of them out of Lego and dreaming of the days to come when I'd be able to ride a lift to the top of each. Those days did come, but only when I was much older, almost an adult.

And of course by the time those days came things had already changed. Once again the change upset me in an obscure fashion that I couldn't quite put my finger on. A lot of my reference books were relatively old and it was only some time after the fact that I was to discover that The Way Things Were had changed again. I'd made my peace with the existence of the Empire State Building and had accepted it as the Tallest Building In The World. So it didn't sit well with me when I found out that this title had been stolen by the twin towers of the World Trade Center in Manhattan. Somehow the new champions being in the same location as the old seemed to be adding insult to injury.

But I came to accept it and eventually added the World Trade Centre to my bucket list of towers (on this occasion I never made it).

But things continued to change. Apparently something called the Sears Tower in Chicago was now the tallest building in the world. And what was worse, the Post Office Tower was no longer the tallest building in the UK - it had been supplanted by the Nat West Building in the City of London, again rubbing salt into the wound by being constructed within the sight of the former record holder.

By the time One Canada Square was constructed at Canary Wharf and took the title I had more or less given up although there was something about the winking light at the apex of the pyramid on its roof that used to draw my attention whenever I looked out over east London.

Nowadays you can't move for skyscrapers. London is thick with them and I'm in danger of losing track of which one is tallest. The Shard - currently tallest building in London, the Post Office Tower now having been demoted to a shocking 11th - is comparable in height to the Eiffel Tower and no doubt will itself be supplanted in due course. Furthermore there are now so many all over the world in a multitude of countries that I can no longer entertain any hope of visiting them all. And they just keep getting taller. The Kingdom Tower in Jeddah threatens to be over a kilometre high. That's ridiculous.

Many of my childhood obsessions are eventually dismantled by the complexity of adulthood. My interest in the London Underground has had all the fun taken out of it by the addition of the Overground and Crossrail to the network, transforming the once beautiful map into a tangled mess. And my love of towers has been derailed by the sheer numbers of them springing up across the globe. I can't keep up.

Nevertheless when the i360 opens in Brighton this summer I will be queueing for a ticket despite the vertigo that seems to have started colonising my fears as I grow older. I finally have a local tower to visit. And as luck would have it, it's nearly as tall as the original Post Office Tower was all those years ago, falling just 28 metres short.

After that I'll look into going into suspended animation until the space elevator is completed.