A vivid picture of everyday life across London - this most dynamic, fast-moving of cities - is what I have tried to capture in my book London Voices, London Lives. It is an account, in their own words, of the people who live and work in the city.

Perhaps because our research took us to places that attracted more than their share of newcomers (most of whom were immigrants) we found many people who were struggling to make ends meet. They told us that they were coping, but only just; they felt they were constantly at risk of going under. Aspiring younger couples said they needed two incomes to survive. And those who lacked a supplementary income - such as lone mothers with small children - found life an endless struggle. Worst off were those assailed by a combination of poor health and the resultant unemployment: for them, existence could become a nightmarish struggle to survive.

Again and again, the basic London divide is between those who have the resources to contemplate buying their own home and those who depend on social housing. In the areas of social housing we looked at, both old residents and new residents found they had little or no control over their lives, leaving them in housing they hated. Others feared they could be impacted by new and difficult neighbours arriving without consultation and without warning. There may appear to be a racial element here; but the real reason often seems to be a clash of lifestyles, particularly associated with age: an influx of younger noisy partygoers on to a peaceful estate of older people, for example.

Likewise, we found owner-occupiers who feel that their neighbourhood has declined because "the wrong kind of people" have come in. Again, there often seems to be a racial element, but it is far from simple. An older African-Caribbean woman in Newham, east London, complains about the arrival of Muslims from the Indian subcontinent, while Indians in Heston, west London, complain about newly arrived white asylum seekers. They tell of rising crime levels, they object to owner-occupiers who have disappeared and let their homes to irresponsible tenants and, above all, they talk of falling standards in the local schools. Many are planning to leave and they quote cases of neighbours who have already gone. They describe their own exit plans in detail, and some are in the course of moving.

Owner-occupiers described their aspirations to have more space in and around the home, plus rural surroundings - but they could not move far because of the need to be close to aged parents, and the constraint of the daily commute to central London. Those in new estates on the edge of London complained about the pace of physical change: the endless construction, including heavy traffic, the steady erosion of a sense of tranquillity, the stress and strain of the long commute to work (whether by car or train), and the need to travel for shopping or other basic local services.

Catchment areas

For those with children, schools were the major concern. Every parent seemed to talk endlessly about it; all seemed well-informed about the merits and demerits of the choices on offer. Some had moved, others were contemplating a move, to the catchment areas of what they regarded as good schools - but even more so in order to avoid what they saw as bad schools. Education appeared a key factor for those moving from inner London to the outer London suburbs or beyond. Again, there was a racial element, but it was complex. An Indian mother in Newham said the family was moving out because the local schools were overwhelmed by new arrivals with learning problems, for example.

The real problem for such parents, however, was not racial but cultural. And their concern, they insisted, was to maintain schools that were truly multiracial and multicultural. Many wanted that experience for their children, but were desperately worried because they saw their local school filling up almost exclusively with children from one culture or religion. Interestingly, we found this expressed not exclusively by white people, but by people of other races and cultures. Some of those most concerned, who were moving or contemplating moving, were British-born Indians faced with an influx of asylum seekers' children.

It clearly mattered to almost everyone that they felt comfortable and settled in their local neighbourhood, with a general sense of physical security and with neighbours they felt were congenial and to whom they could turn in an emergency. In this sense, you might say that almost all Londoners across the eight areas in which we carried out our interviews shared middle-class values. Most did have such a sense of living a good life in a good neighbourhood but a minority clearly felt they did not, and sometimes this seemed to cloud their entire view of their world, giving them a general sense of insecurity and anxiety.

It invariably appeared to reflect the presence of relatively few antisocial young people. In some neighbourhoods, especially in parts of outer London, there was a more general feeling that the area was going downhill, that the former sense of community had been eroded, that everyone was leaving and that it was essential to join the stampede as soon as possible. In these areas there was a sense that newcomers were bringing with them an erosion of the entire social fabric.

But such areas remain unusual. Generally, London's story has been a quite different, even contrary, one: a story of almost constant change and instability, as new groups came in and older groups moved out. Gants Hill, where Bengalis follow Jews out of the Whitechapel ghetto to the suburbs, is typical of such a place. What has happened in London in recent years is simply that the extent and the speed of such changes has become much greater, affecting many more areas rapidly. And since we finished our interviews, the process seems to have become even more frenetic. But perhaps this is London's quasi-permanent condition, as true of the 1890s age of immigration, or of the 1930s spread of semi-detached suburbs, as it is today.

· Sir Peter Hall is Bartlett professor of planning and regeneration at University College London. This article is adapted from his Michael Young memorial lecture in July. London Voices, London Lives is published by Policy press (RRP ·24.99). To order a copy for ·22.99 with free UK p&p go to theguardian.com/bookshop or call 0870 836 0875