4.4 million people. That's roughly the same population size as the Republic of Ireland or Croatia. Half of London. Or, put another way, four more Birminghams.
That is the increase in the UK's population over the next decade, according to the Office for National Statistics. And it throws up major questions about 'social integration' - the extent to which people in Britain interact with others from different backgrounds to their own.
Ever since Thomas Malthus published his book An Essay on the Principle of Population in 1798, there has been much public debate about population growth and what this means for life in Britain.