What's the big idea?

I have never been much taken by the "dumbing down" argument – the one that says cultural fings ain't wot they used to be. I am just about old enough to remember when BBC TV was wall-to-wall Eamonn Andrews and Dixon of Dock Green, so I know inanity on the telly is nothing new. And yes, my German A-level papers look a lot harder than those the modern day students take, but I'm not sure how you convincingly compare a past when such a small proportion of the age group entered higher education against a present when so many more people go to university.

However, my agnosticism about dumbing down may not survive last week's Great Announcement by deputy prime minister John Prescott. It came strangely unadorned by "big picture" argument or much of what you might call intellectual underpinning, and that surely marked it out from previous efforts to map the urban future.

The day of the announcement, I happened to be at a seminar where Mike Ward, chief executive of the London Development Agency, was speaking. He rattled off a string of precursors – Lord Reith's study of London during the Second World War, the Abercrombie report, Sir Peter Hall's work over the years.

Decline in the quality of the urban argument did not set in with Labour's arrival in power. The official paperwork surrounding the abolition of the Greater London Council by Margaret Thatcher in 1986 was pitiful in the level of insight it displayed about what you might call the geopolitics of the South-east – the relationship between the London conurbation and the wider South-east and, above all, what the consequences for region and nation are from London's role as a global city.

It may sound like a cliche but it reflects historical and contemporary reality. London has made a stupendous transition from imperial capital to world city, with a marked bias towards finance capital. In both cities, social divisions were sharp. In both, too, London's size and economic potency have marked effects on the region, let alone the rest of England.

Where is the big idea behind the East Thames expansion? What kind of communities will these Prescottvilles be?

What Prescott's statement might have given us was a qualitative sense of the place of the South-east in, if not a global, then a European context. Does the government accept the "banana" model, used to describe that curve of prosperity from Oxford through Strasbourg to Turin? We were entitled to expect, from a Labour minister, more of a "social" sense of what this physical expansion of the South-east entails.

New Towns – a Labour idea that the Tories willingly took to – embodied an idea. It was a mistaken idea – that somehow proximity to fields and open spaces would wash away problems of jobs and income – but at least it was a concept. Where is the big idea behind the East Thames expansion? What kind of communities will these Prescottvilles be?

There are two reasons why the plan is so sketchy. One is Labour's hesitation in coming to terms with the South. The party's political identity is still bound up with its manufacturing, Northern past and around the Cabinet table sit MPs for, mainly, north of England or Scottish seats. Eventually, that electoral geography will change. Perhaps the Prescottvilles will return Labour MPs. But for the time being there is a stark mismatch between Labour's territorial affinities and its policy commitments.

The second reason goes to the heart of Blairism and has to do with New Labour's historical compact with "market forces". Both the prime minister and the chancellor, allegedly rivals but in fact intellectually united on this key point, believe one cannot buck the market. Gordon Brown says firmly that there are certain areas, such as health, which should be market-free, but – as he said in his big speech last week – when it comes to infrastructure or public services at large the market works well. As for goods and services at large, he believes there is no alternative: market forces rule. The markets, moreover, love the south-east of England. So that is where the state should provide, following commerce like the man with the cart following the horses in the big parade.

Prescott's plan is an acknowledgement that government responds to market pressures rather than – as Labour used to believe – trying to make and mould markets for the sake of wider public interests. Once Labour believed you could issue permits for offices or factories, that you could even tax employment in order to favour certain classes of work – manufacturing over services, say.