Two or three years ago, everybody I met seemed to be thinking of moving to New Zealand. At the time, I put it down to the arrival on our cinema screens of Peter Jackson's The Lord of the Rings, with its ravishing depiction of South Island landscapes, and wondered if it was a passing fad. Then I got an airmail letter out of the blue from one of those sojourners, an old friend, who announced that he'd actually done it - almost. He and his partner had moved to the eastern seaboard of Australia and, although it wasn't quite South Island, it did have environmental quality in abundance. "I think the amount of space people have here, whether it's at home or on the beach, is one of the big bonuses . . . people seem much happier and more relaxed as a result."
Most people in the UK could these days tell a similar story, of people they know who have moved "out" - wherever "out" might be - in search of a better life. And though it is conventional to decry such anecdotal evidence, condescension, in this case, would be misplaced. Demographics - the study of population, its growth and movements - is in a fundamental sense an attempt to capture in statistics the lives that anecdotes describe. And there is little doubt that such anecdotes embody something real, and worrying.
Take second homes, for example. People own them in some remarkably far-flung places - ski resorts in Canada, villas in the West Indies. These are not always very wealthy people; owning a second home is turning into a middle-class norm. Officially, there are 151,000 second homes in England and Wales - but they come a poor second to property owned abroad. The industry estimates that there are 750,000 homes in Spain owned by British nationals, roughly 500,000 in France, and many more in places such as Florida, Portugal, Mediterranean countries other than Spain, and, increasingly, eastern Europe. So at least 1.5 million British households - roughly 6 per cent of the total - have given up sufficiently on their "normal" lives to want to half-live somewhere else. And that is just those who can afford it.
But half-living somewhere may be only a stepping stone to moving there: some observers call it "pre-emigrating". Surveys recently have uncovered huge numbers of Britons who, given a free choice, would get out of the country. Separate polls by ICM and YouGov found that more than half would like to leave - the YouGov poll found that 55 per cent had "seriously considered settling in another country". A recent survey by the offshore bank Alliance & Leicester International and the Centre for Future Studies put the proportion of Britons "considering moving abroad to work or live" at a third. Based on these figures, the bank projects that by 2020 an extra six million British citizens - more than one-tenth of our current population - will be living or working abroad. Roughly four million of these will be people aged 50 and above - representing one in five of that age group.
In historical terms, such figures would represent a huge population exodus - far bigger than that caused by the Irish potato famine in the 19th century, for example. Are they realistic? A projection - or, come to that, a pipe dream - is one thing. Getting off your backside and doing it is something else again. But getting off our backsides is what, it seems, more and more of us are doing.
Over the past dozen years or so, some remarkable changes have occurred in Britain's demography. London's long-standing population decline has halted, and the capital's "recovery" (in economic growth and numbers) appears to have accentuated the north-south divide. It also appears to have accelerated the metamorphosis of much of lowland England, south and east of a line from the Wash to the Bristol Channel, into a kind of infinitely greater London - a peri-urban zone where the landscape may look rural but the lifestyles, noise and congestion are metropolitan.
At the same time, national population growth has taken off again, driven primarily by immigration and by the greater fertility of newly immigrant populations. Yet while most of the attention, regrettably or otherwise, has centred on immigration, the complementary emigration "problem" has been all but ignored. This is partly because, when you put the two together, Britain has more incomers than outgoers, and thus a net inflow of population. If everyone wants to come to the UK, we must be doing something right, surely? Yet this net inflow conceals a dramatic rise in the numbers of emigrants - and some significant changes in their make-up and destination.
In the early 1990s, incomers and outgoers were roughly in balance. Indeed, in 1992 and 1993 there was a net outflow of migrants. Since then, however, while the number of immigrants, using official figures, has nearly doubled, from 265,000 in 1993 to 513,000 in 2002, the number of emigrants has also increased, from 266,000 in 1993 to 359,000 in 2002. This last is the highest figure in the past two decades - and slightly higher per head of population than emigration from Ireland - and may well be the highest number ever.
Given that emigration is supposedly associated with economic failure and the government is forever telling us how successful Britain has become, this is something of a mystery - for the economically minded, at least. When you also note that, according to historical poll evidence, people are much keener to emigrate now than they were even during postwar rationing and the strife-torn 1970s, economic explanations start to falter. So do easy assumptions about globalisation, increased foreign travel, the proliferation of TV programmes showing us how to grapple with Provencal plumbers or Normandy notaires. These help to explain the pull, but not the push, factors.
Government statistics are not especially helpful in profiling the new emigrants. But they do tell us that increasing numbers were born in the UK, that they are getting older, that they include a growing proportion of the professional and managerial classes, that they are leaving for longer (four years or more), that a disproportionate number of them come from London and to a lesser extent the south-east, and that the fastest-growing destinations are Europe and the "old" Commonwealth - countries such as Canada, Australia and New Zealand. As to why they are leaving, 30 per cent mention work but 51 per cent give "other" reasons.
These are not hard to find. A survey in Emigrate magazine found that roughly three-quarters of potential emigrants think quality of life in Britain is deteriorating. The YouGov poll cited crime, council taxes, congested roads, lack of space. Eighty-five per cent thought Britain was "grinding to a halt". ICM added a few more reasons to be miserable: bad weather, long working hours, regional unemployment, high house prices. The Alliance & Leicester study found that the top reason for emigration was the search for a better quality of life, with work stress the main trigger, and destinations which place a "greater value on leisure and lifestyle" the most favoured. Among older people, the main reasons for moving abroad were climate and environment, pace of life, health, lower living costs, and "social advantages". What is also notable throughout such surveys is gloom and pessimism about Britain and the lack of attachment to the homeland.
You can draw a number of conclusions from such findings. One is that Britain's deregulated US-style economy, whatever its financial fruits, appears not to be delivering the goods in terms of well-being or happiness - a point made in a number of recent studies, most notably the New Economics Foundation's Chasing Progress. A second is the rise in both immigration and emigration since the early 1990s. Is there a causal link? The left might not like the idea, but it may be that one of the things against which people are voting with their feet is enforced multiculturalism - a possibility given extra credence by the fact that, in 2002, more than half of in-migrants to Britain were making for London and the south-east, while 47 per cent of out-migrants were leaving London and the south-east.
A third is that such large population shifts may presage sea changes in British society. It is safe to assume, for instance, that although many of the immigrants to the UK will be younger people keen to improve their economic lot, many of the emigrants will be less concerned with worldly goods: they may already have enough to survive. Over the past two decades, various labels have been invented to describe such people: downshifters, "post-materialists" - in short, people who are nearing the summit of what the American psychologist Abraham Maslow called the hierarchy of needs, and are increasingly in search of personal and spiritual fulfilment. And if that is so, then the slow substitution of one lot for another over the next two decades could make Britain an altogether harder-edged place - more "dynamic", maybe, but also more aggressive, competitive and stressful. And because crime is largely a phenomenon of youth, it may also be more violent, or at least criminal.
Trying to deconstruct portfolio terms such as "quality of life" is notoriously difficult. So is finding one cause for a phenomenon into which several other apparent causes can be subsumed. Yet it is possible we have been here before. The demographic feature that more than any other has redrawn the postwar map of Britain is flight from the cities - counter-urbanisation. Like Britain's new wave of emigration, this was ascribed to a search for quality of life, but the statistical measures that described it most accurately were crowding and density. The bigger and more crowded a place, in other words, the faster it lost population.
Are Britain's new emigrants the counter-urbanisers of the third millennium? Such an explanation would certainly fit major features of the outflow - the popularity of "spacious" destination countries, and the general perception, confirmed in surveys, of an overcrowded homeland. As, indeed, by international measures, it is - lowland England is probably more densely settled than any other area of comparable size in the developed world. Moreover, many of the policies the government seems set on - deregulated economic competitiveness; the promotion of immigration as a source of cheap labour and a way of filling vacancies; "predict and provide" policies on housing, roads, air travel - will only make that worse, creating an environment which is good for economic growth but bad for people.
Bad enough to make them want to get out.
David Nicholson-Lord's Green Cities - And Why We Need Them (2003) is published by the New Economics Foundation