Record-high fertility rates led to the UK population reaching 61.4 million in 2008.
The increase of 408,000 more people living in Britain last year is the largest yearly increase to be reported since modern records began in 1972. The Office of National Statistics, who completed the research, has also confirmed that the increase in population was the highest in nearly 50 years.
Population increases of 484,000 in 1962 and 551,000 in 1947 are the last times the figure was topped. The highest fertility rates in Britain for a generation have been attributed with driving up the figures.
A decade of high immigration driving up population stats has now been replaced by shifting birth and death rates.
Immigration has actually slowed down extensively since the start of the economic downturn after the mass waves of immigrations from Eastern Europe Britain saw in 2004.