The population is projected to increase by three million, or 4.5 percent, from an estimated 66.4 million in mid-2018 to 69.4 million in mid-2028.
ONS said England's population is likely to grow more quickly than the other parts of Britain, increasing five percent between mid-2018 and mid-2028 to 58.8 million, compared with 3.7 percent for Northern Ireland (2 million), 1.8 percent for Scotland (5.5 million) and 0.6 percent for Wales (3.2 million).
The analysis shows that over the next 10 years, 27 percent of Britain's population growth is projected to result from more births than deaths, with 73 percent of growth resulting from net international migration.
Statisticians estimate that Britain's population is projected to pass 70 million by mid-2031, reaching 72.4 million by 2043.
ONS said there will be an increasing number of older people, with the proportion aged 85 years and over projected to almost double over the next 25 years.
Britain's population in 1993 was 57.7 million, passing 60 million in 2004.