New statistics taken from NHS records of women who have just given birth show that white Britons now account for an average of just six in ten of those receiving maternity care.
They also reveal the startling changes that a decade of record migration is having on different parts of the country.
In some inner city areas the proportion of white British mothers slumps to fewer than one in ten. But the impact on parts of Middle England is even more staggering.
NHS trusts which cover parts of the home counties - such as St Albans - report less than six in ten mothers are white British.
The figures will reignite the debate about the scale of immigration and the scale of social division, as well as the impact on public services.
Ministers have pledged to force migrant workers to buy their own private health care to help reduce the burden on the NHS.
Under the proposals non EU migrants would be entitled to emergency care but would have to buy insurance to cover the costs of GP visits and most operations.
The statistics raised fears the country is becoming increasingly divided along ethnic lines.
Of 652,638 deliveries in 150 NHS Trusts in England last year an average of 62 per cent of mothers were white British. But in some parts of rural England more than 95 per cent of mothers fell into that category.
These included North Devon with 97.4 per cent, Co Durham and Darlington with 97.1, and Northumbria with 96 per cent.
But at the other end of the spectrum, North West London NHS Trust - which covers Harrow - just 9.4 per cent of mothers were white British.
Another inner city trust - Sandwell and West Birmingham - had just 16.5 per cent. Just over one in four mothers were white Britons at Guy's and St Thomas's hospital in central London.
But the West Hertfordshire NHS Trust, which covers St Albans, just 57 per cent of mothers giving birth were of white British origin.
Of the remaining 43 per cent, the biggest groupings were 'other white' - which includes Eastern Europeans - Indians, Pakistanis and Africans.
Backbench Tory MP Douglas Carswell said: 'I think we have to face reality and that is if you continue to have mass immigration it's going to have a very significant impact on the demography of
Last month it emerged that Britain's population growth is outpacing every other country in Europe.
Immigration and rising birth rates driven in part by the children of new arrivals - the so-called 'immigrant baby boom' - meant this country gained more people than anywhere else in the continent.
There were also warnings last week that Hungary is set to hand two million passports to people living outside the EU.
Ministers have pledge to put a limit on the number of immigrants from outside the EU given work permits for the UK.
David Cameron has pledged to reduce the level of net migration - those arriving minus those leaving - from the hundreds to the tens of thousands.
