A report on population dynamics of UK city regions, published this week by the Office for National Statistics, reveals that the population of the eleven biggest city regions rose from just under 26.3 million in 2011 to 27.1m in 2015, with Greater London alone showing a growth of 469,000 during the period. For the purposes of the rsearch, the ONS defined city regions as metropolitan centres and their functional areas.
The report projects that the growth will continue, with a 7.6 per cent growth in city region population projected between 2015 and 2025.
The population of Greater London is expected to reach almost ten million by 2025, the figures suggest, whilst the West Midlands' population is projected to breach the three million mark.
Other city regions projected for significant population growth rates to 2025 include Bristol (8.9 per cent), Greater Manchester (5.9) and Edinburgh (7.3).
Greater London has a much higher international migration growth rate than the other city regions, the report says.
"On most measures shown in this report, Greater London stands out," it says.
"It is by far the UK’s largest city region but is also the fastest growing. Its attraction as the UK capital, a major employment centre and international hub lead to much higher growth from international migration from any other area."
The report suggests that, for the other city regions, there are wide variations in trends and that "city regions are not inherently distinctive in terms of population dynamics".
The report warns that whilst the figures are "useful for planning purposes" they are not predictions, and that the figures could be affected by various factors, including Brexit.
"Changing levels of economic success, both locally and nationally, are likely to be an important factor", it says.
"And, dependent both on the economic effects and potential changes to migration law, the UK’s June 2016 vote to leave the European Union is likely to have an impact."