The UK population is projected to rise to 72.5 million by mid-2032 from 67.6 million in mid-2022, driven almost entirely by net migration into the country, the Office for National Statistics said on Tuesday.
Britain has seen record levels of immigration in recent years, and the ONS projections may fuel a debate over the ability of strained public services to cope with population growth and the need for foreign workers to drive the economy.
Successive administrations including Labor Prime Minister Keir Starmer's government have vowed to reduce immigration - a hot political topic that helped lead to the Brexit vote in 2016 and has fueled the rise of the right-wing Reform UK party.
Net migration - the number of people arriving minus those leaving - of 4.9 million people is projected to drive the population increase over the 10-year period, the ONS said.
The number of births and deaths in the UK over 2022-2032 was projected to be similar, the ONS added, largely cancelling out the impact of any natural change to population.
Although births were projected to increase slightly, deaths are also expected to go up as the large cohort of those born in the two decades after 1945 get older.
The projections also assume a long-term net migration level of 340,000 per year from the year ending mid-2028 onwards, the ONS said.
Net migration reached a record of more than 900,000 in the year to June 2023.
ONS data showed last year that the UK's population had grown by 1% in annual terms to 68.3 million as of mid-2023, mainly due to immigration.
While post-Brexit changes to visas fueled a sharp drop in the number of European Union migrants to Britain, new visa rules led to a surge in immigration from India, Nigeria and Pakistan, often to fill health and social care vacancies.
