You don’t need a soothsayer,  just a demographer.

Immigrant mothers are having far more children than their British counterparts - fuelling the biggest rise in population since the 1960s baby boom.

The proportion of births to foreign mothers is up by a third since 2001 and by almost half since Labour came to power.

Fertility rates are at levels not seen for 25 years, with the highest found among Pakistani, Indian or Bangladeshi-born mothers. Those nationalities alone accounted for five per cent of all British babies last year.

A further four per cent were born to mothers from EU countries outside Britain and Ireland, with a growing number from eastern Europe - mainly Poland.

The Pakistani rate of 4.7 children per mother is almost three times the British-born rate of 1.7.

The study, by the Office for National Statistics, is the latest to chart the impact of record levels of immigration, which took off when Labour came to power in 1997.

It showed that 154,000 of the 749,000 births in 2006 - 21 per cent - were to immigrants. This compared to 12 per cent in 1996 and 15 per cent in 2001.

The study predicted that almost 70 per cent of the 10 million rise in population over the next 25 years would be down to immigration - either directly or via higher birth rates.

David Davis, the shadow home secretary, said: “It is long past time the Government came up with a proper population strategy.

“The figures show the impact immigration can have on the public sector infrastructure, including schools and hospitals, and why the Government must answer our calls to take these factors into account. Immigration can be of real benefit to the country, but not all or any immigration.”