PEOPLE in Britain are living longer and having more babies—and more foreigners are joining them. That is the main finding from the 2011 census results released on July 16th. The population of England and Wales is growing faster than most demographers thought, at 7.1% for the decade, thanks mainly to immigration and a rise in fertility fuelled by the newcomers. But there is another, still less expected, change: big cities that were shedding people a decade ago are growing at a terrific rate.

London has been swelling since the late 1980s, but its rate of growth has increased sharply. All eight of England’s “core” cities outside the capital have expanded, whereas only one—Leeds, in West Yorkshire—grew even slightly between 1991 and 2001. For years, as manufacturing jobs ebbed from the Midlands and the north and city centres decayed, big conurbations like Liverpool and Manchester tended to pull down their region’s performance, points out John Salt of University College London. No longer. Newcastle, for example, grew by 5% in the past decade as the North East virtually stood still.

Three things have contributed to this resurgence. The first is the investment in reclaiming city centres, inspired partly by Lord Rogers, an architect and urban booster. The middles of once-hollow cities have been filled with flats just as constraints on the use of green land around many of them have tightened.

Another is jobs. Public-sector investment under the last Labour government created well-paid work outside the south-east. Big-city universities have grown, attracting both British and foreign students. As cities have improved, more graduates want to stay on in them. Employers are drawn by a skilled labour force, and the virtuous circle attracts other newcomers.

The third is immigration. Census figures on national and ethnic origins are not yet out, but many of the places that have seen the greatest increase over this past decade of unprecedented immigration are those where newcomers have historically been most apt to settle. Manchester’s population grew by 19% in the ten years to March 2011, much faster than its surroundings (see map). Not so long ago the city centre housed a few hundred people. Now it holds perhaps 15,000-20,000, as students and professionals have moved in droves into converted warehouses and factories. In Manchester, the number of residents between 20 and 40 years old has increased spectacularly, and with it the number of children. There are 43% more twenty-somethings, and the number of those who are aged four or younger is up by 40%. It is an extreme example of a national trend (see chart).

Manchester’s expansion is not entirely due to a yuppified city centre. Moss Side, a run-down district once famous for gun crime, is also growing exceptionally quickly. On a street near the former Maine Road football stadium, a little girl clings to her hijab-wearing mother as they enter a once-abandoned Victorian terraced house. The authorities estimate that Moss Side’s population grew by 30% between 2001 and 2011, driven in large part by an increase in the number of young families, mainly immigrants. Somali is a close second to English as the most-spoken first language in Moss Side schools. London too has been growing faster than number-crunchers thought, says Baljit Bains, head of the Greater London Authority’s demography unit. With over 8.1m inhabitants now, the capital is set to surpass its 1939 peak of 8.6m by 2016—especially, she believes, if euro-zone woes lead to an influx of people looking for work. Ethnically diverse Tower Hamlets in the East End has the highest population growth of any local authority, at over 26% in the past decade. Its neighbour Newham is hard on its heels. By contrast, population fell slightly in banker-heavy Kensington and Chelsea—thanks partly to the sale of glitzy properties to absentee Russian oligarchs and the like. There are signs that sky-high property prices are pushing poverty from the centre to the periphery. Are urban populations growing because people want to live in cities again or because they have to? It is a mixture of the two, says Tony Travers of the London School of Economics. Moving to London generally enhances a career because so many companies are based there and people change jobs a lot—the so-called “elevator effect”. This may just about be true of Manchester. Lately sticky jobs and housing markets have glued urbanites in place. But supply makes a difference, too. As big cities have welcomed growth in their centres, many small towns have resisted it.

The return to city living is not unique to Britain. Berlin and—at least until recently—some southern European cities have also been growing strongly. In America, the foreclosure crisis has pushed people back into cities and inner suburbs, says William Frey of the Brookings Institution, though it is not clear whether that trend will last.

The question is whether England’s big provincial cities will keep growing. So far, new arrivals have squeezed into redeveloped flats and dilapidated Victorian terraces. But as Sir Howard Bernstein, Manchester’s long-serving chief executive, points out, to thrive a city needs to attract “aspirational” families. Decent family homes are still in short supply—as are decent schools.

Britain’s cities flourished during its long economic boom. But many were boosted by public-sector job growth, now over, and may be losing steam. Though some—Bristol, Leeds and Manchester especially—have kept their heads above water, job-creating dynamism seems once again to be mainly in southern and eastern England, and especially the capital. The census is merely a once-a-decade snapshot. It may have captured an urban resurgence that is already waning.