“It assumes net migration - the difference between numbers arriving and leaving - remained around its current record level of 240,000 a year.

Ministers pledged to cut it to the ‘tens of thousands’ by 2015.

Two-thirds of the population rise is due to immigration, including an ‘immigrant baby boom’ caused by higher-than-average birth rates among migrant mothers.

Commentators said the analysis shows the ‘absolute necessity’ of cutting the number of migrants coming here.”