London's population is set to jump to just under 10 million by the middle of the next decade, official figures indicate.
The number of people living in the capital will reach 9.7 million in mid-2024, according to projections.
This amounts to a rise of just under 1.2 million, or 13.7%, compared to the level 10 years earlier.
The East (8.9%) and South East (8.1%) regions are also set to grow at a faster rate than the rest of England as a whole over the decade from mid-2014, according to a new study published by the Office for National Statistics.
Of the projected growth in London, natural change - the difference between births and deaths - is expected to account for 10.4 percentage points of the growth.
The remaining 3.2 percentage points are attributable to migration, resulting in part from a 10.2 percentage point increase from international migration - equivalent to around 870,000 people. This is offset by a change of minus seven percentage points from "within UK" migration - meaning there is a net outflow of people from the capital to other parts of the country.
The figures were revealed as statisticians published a breakdown of the estimated growth in the number of people living in regions and local authorities.
Previously published projections showed the population of England as a whole is expected to rise by more than four million over a decade to reach 58.4 million in 2024.
Nine out of the 10 local authorities with the highest projected population growth between mid-2014 and mid-2024 were in London.
Projected change for local authorities ranged from a fall of 4.3% in Barrow-in-Furness, Cumbria, to growth of 25.1% for Tower Hamlets in east London over the 10 years.
The number of local authorities in England where more than a quarter of the population are aged 65 and over is projected to increase from 28 out of 326 in mid-2014 to 84 areas in mid-2024, the report added.
Suzie Dunsmith, of the Population Projections Unit, Office for National Statistics, said: "All regions of England are projected to see an increase in their population size over the next decade, with London, the East of England and South East projected to grow faster than the country as a whole.
"The population is also ageing with all regions seeing a faster growth in those aged 65 and over than in younger age groups."
Simon Ross, chief executive of the charity Population Matters, described the figures as "a wake-up call".
He added: "High rates of population growth are projected across many of England's regions. This has substantial implications: we will be struggling even harder for school places, health services will be further stretched and the housing crisis will spiral even further out of control.
"And if these projections are right, it is not only affordability and quality of life that will suffer, but air quality, biodiversity and the wider environment.
"Policy makers must sit up and take notice. More must be done to educate, inform and raise awareness about the benefits of sustainable population and family size."
Alp Mehmet, vice chairman of campaign group Migration Watch UK, said: "The population of England is projected to grow by 4.1 million over the next 10 years, the majority of which is down to the effects of international migration.
"The country is already facing a housing crisis and there is huge pressure on GP services. Meanwhile there is projected to be a shortfall in primary school places in the very near future. These figures can only make a bad situation a whole lot worse."