Firstly, two generations have passed since the last of Britain's first wave of controversial concrete council tower blocks was built. Attitudes have changed. Babies born then are now in their early thirties and have had children of their own. All their lives, they have been used to the old towers - several of which are now officially sanctified by English Heritage. They are no longer seen as a problem.

Secondly, technology now allows skyscrapers to be much more clever. Structural engineering, improved materials, computer-aided design and wind testing have all come on in leaps and bounds in the past 20 years. You can design towers today of an ambition and elegance which would have been impossible - or impossibly expensive - back then. So architects and developers have rediscovered a taste for building landmarks.

Thirdly, the Government and its advisers since 1997 have encouraged high-density building, especially in cities, as an antidote to suburban sprawl. So too does London mayor Ken Livingstone and the leaders of many cities around the country. High-density does not necessarily mean towers, but with towers you can in theory have more open public space as well. Urban landscaping is as big a growth area as urban architecture.

Fourthly, the property boom has stimulated a private-investment bubble in "buy-to-let" apartments. Today, apartments in high-rise apartments attract premium prices and rents. So people are queuing up to build them and trade in them. This bubble must soon burst, but for now it is growing like mad.

And finally - can it be said that we are a bit more aesthetically confident than we used to be, as a nation? After the political battles and traditionalist backlash of the 1980s, and the devastating economic recession of the early 1990s, a new, more upbeat mood started to emerge. We live in an internationalist era of cheap flights where people habitually compare one capital city to another. We are, in short, not so parochial.

But a word of warning. You don't make iconic buildings simply by building tall. A bad tall building is still a bad building, and unfortunately more people see it. Tallness is not the same as godliness. Put it this way: only the best architects need apply. Please.