LONDON, June 23 (Xinhua) -- City center living is growing fastest in Liverpool than any other provincial city in Britain, researchers from Center for Cities said in a recent report.

Paul Swinney and Andrew Carter said a generation ago many downtown areas of British cities were dreary and dilapidated places, with a reputation for crime.They are now among the most desirable areas of the country to live, posing the question: what's changed?

"Take a walk through the centers of Manchester, Liverpool and Birmingham and you will see smart new high-rise apartments, office blocks and the ever-present cranes building still more," they said.

Street level cafes, bars, restaurants and gyms serve their often young and affluent customers, the people who increasingly define these areas, added the two researchers.

"Thirty years ago inner city populations that had grown rapidly in the late 19th and early 20th centuries had dwindled, the residents leaving cramped, urban housing for more spacious suburbs and new towns,"they saidin the report.

The reversal that has taken place, especially in the north of England and the Midlands, demonstrates a dramatic urban renaissance and a shift in how people want to live.

They say that since the start of the 21st century the population of many town and city centers has doubled in size, while the population of Britain has increased by 10 percent.

Between 2002 and 2015 Liverpool's 181 percent growth in city center living was the highest, followed by Birmingham (163 percent), Leeds (150 percent) and Manchester (149 percent). Close behind were Bradford, Leicester and Sheffield.

In terms of sheer numbers the fastest growing city center was London, which grew by a relatively low 22 percent from 268,700 to 327,200.

Sweeney and Carter said the growth in city center living is down to young people, with older generations not returning from the suburbs in significant numbers.

Students have made up a proportion of the increases as their numbers grew with the expansion of university education.

"But the popularity of big city centers among young, single professionals is the main factor," Center for Cities added.

The number of 20 to 29-year-olds in the center of large cities tripled in the first decade of the 21st century, to a point where they made up half of the population.

Only one in five city centre residents were married or in a civil partnership, while three-quarters were renting flats and apartments.

More than a third had a degree, compared with 27 percent in the suburbs and outskirts of cities.

A big pull for young professionals has been the growing number of high-skilled, high-paying office jobs available.

To some extent, governments have supported these trends, with the urban development corporations of the 1980s sparking the regeneration of city center sites such as the Albert Dock in Liverpool and the Castlefield area of Manchester.

The face of many cities continued to change in the early 2000s, as Labour invested significantly in urban regeneration programs.

Center for Cities said for the most successful city centers, increased demand from both residents and businesses raises important questions about the future.

"Until now, places like Birmingham and Manchester have had lots of land to develop, as they recovered from their post-industrial decline.

"But over the next 10 years the challenge will be meeting demand for housing without squeezing the commercial heart of the city centers.

If they are to continue attracting high-paying jobs, city centres might have to prioritise businesses," added the researchers.

"A bustling, vibrant city center is often a source of civic pride, a struggling city centre can become a symbol of broader social problems and decline. This is why people care so much about the future of their city centers and want to see them thrive," they concluded.