The EU's statistical office Eurostat said in its report that by2060 the country's population is to increase from the current 61 million to almost 77 million.
If the predictions come true, Britain will be the most populous EU country in 2060.
In the mean time, said the report, the average age of the EU population will rise due to "persistently low fertility and an increasing number of survivors to higher ages."
Those aged 65 or above in Britainare projected to grow from 16.1 percent in 2008 to 24.7 percent of its population in 2060. And the number of Britons aged 80 or above is expected to reach 9 percent in 2060, compared with the current figure of 4.5 percent.
If the projection is correct, 42.1 percent of Britain's population would be above retirement age by 2060.
Britain has introduced the biggest change to its immigration system for a generation to curb sharp rise in migrants, especially those from outside the EU, to relieve increased pressure on education, employment and public services.
