This is pretty much what the volume housebuilders still like to offer their endless queues of buyers today: space and air. Away from the hugger-mugger city. Even though cities are nothing like the overcrowded industrial places they used to be. And even though "countryside" now too often means endless roundabouts, glaring street lights, roaring roads, huge distribution warehouses and rising crime rates. The roles are reversing: cities, now increasingly putting pedestrians before motor traffic, are becoming places to escape to, not from. They are becoming oases.

So the official doctrine has changed. High-density urban living - particularly on those "brownfield" former industrial and hospital sites - is officially good again. Urged on by the Government, every council is rewriting its Strategic Development Plan to accommodate the new orthodoxy, which is exactly the reverse of the old, density-discouraging, orthodoxy. Even away from the centres, new housing developments are now meant to be stacking 'em up rather than spreading them out. And the volume housebuilders have, up to a point, been responding. As well as the standard suburban offer, they now have the standard brownfield offer, which is higher-density and tends to involve named architects more. Housebuilders build wherever the land is made economically available. They go with the flow.

But things are not quite as simple as they seem. High-density does not necessarily mean the loss of open space, as the modernists always knew. It just means that the type of open space changes. Build a tall, slender residential tower, and there is land left over for gardens round the base. Open space can also be created up in the air in the form of sky-gardens and roof terraces. Or you can build densely-stacked courtyard housing, arranged in the Georgian manner in crescents or squares. Again, the result is a surprising amount of open space. But it tends not to be your very own, personally-fenced bit of England. It tends to be more communal. And we're a bit suspicious of that. Because it makes us think of failed council estates - in American parlance, housing projects - surrounded by useless and dangerous patches of open ground. When it should make us think of upmarket, well-tended garden squares accessible to privileged keyholders. As always, it's a social thing. Also a management thing.

So what about what some regard as the most perfect form of housing ever invented by the British - the terrace or row house? With terraced streets, you get everything: your own private front door, your own fenced back garden, and relative high density - depending on how closely the streets are arranged, and how big the homes go. But here's a strange thing. Whereas old terraced houses are generally seen as highly desirable, until recently new terraced houses - except in some high-value locations - usually were not. That is changing rapidly but even today, many typical buyers of brand-new new private houses, out on the edges of market towns, still do not expect to be physically joined on to their neighbours. They want their home to be a castle, and by definition castles are stand-alone objects, even if they happen to be standing alone in a tight crowd. Castles don't come in strips. The latest terraces tend to address this problem by jumbling up the house types so as to help preserve the image of individuality, for instance, while the modern loft aesthetic is starting to be applied to some new terraced developments with success - but it is changing only slowly.

If you talk to the House Builders Federation about this, they will certainly go on about the need for a mix of house types rather than a "one size fits all" policy. They suggest that the drive for density is just another market-distorting factor. In 1997, according to HBF figures, 46 per cent of new homes in Britain were detached houses and 15 per cent were apartments. In 2003, the figures had virtually reversed: 46 per cent apartments and 19 per cent detached. High density, it appears, means only blocks of small flats. What the HBF cannot tell you (I know, because I asked) is why this should be. Why can't you have high-density developments of medium to large family homes?

Partly it is to do with Britain's curious housing market, where people gamble in property futures as a form of investment, without living in the places they buy. The buy-to-let market favours one and two bed apartments. Most of the huge amount of housebuilding going on in city centres at the moment is designed to satisfy this investor demand. Family homes, in the meantime, continue to be built out in rurbania in their mostly detached suburban enclaves. It seems that few can imagine something that combines the two sides of the housing market: developments of family homes, whether in the centre or on the edges, that are just as high-density as the apartment blocks but are suitable for children as well.