Labour's open-door immigration policy led to the largest population explosion since the Saxon invasion more than 1,000 years ago.
An audit of official figures last night revealed that during the party’s 13 years in power Britain’s foreign-born population increased by three million.
At the same time, nearly a million British citizens left the country.
Campaign group MigrationWatch said figures to be published by the Office for National Statistics on Thursday will show that by mid-2010 that total had reached 3.2million.
In recent years, migrants have been arriving at the rate of around ‘one every minute’, the group’s report says.
It comes as a poll found, for the first time, that those in the 16-24 age group were more worried about migrant numbers than those in their 30s.
The 3.2million population increase does not include illegal immigrants – of whom there are around one million in the UK.
MigrationWatch says the ‘three million-plus extra people on this island equates to the creation of three cities the size of Birmingham’.The open-door policy was pursued with no public consultation, the study says.
Sir Andrew Green, chairman of MigrationWatch, said: ‘This has been a clear failure of democracy due in large part to the Left’s deliberate tactic of stifling reasoned debate with accusations of racism.
‘In the years to come, immigration will be seen as Labour’s great betrayal.’
The MigrationWatch document says: ‘Immigration under Labour is certainly the largest ever in numerical terms and the largest in relation to population since the Saxon invasions over a thousand years ago.
‘The only two subsequent immigrations – the Huguenots in the 17th century and the Jews in the 19th and 20th centuries were minor by comparison with recent inflows.
‘Net foreign immigration over the past five years has averaged 24,000 a month.’
The report also says that of the 3.2million immigrants, 80 per cent came from outside the EU, and that, since 1997, 75 per cent of extra jobs created went to foreign-born workers.
It states that more than a third of new households will be a result of immigration – requiring 330 new homes every working day for 23 years.
And it points out that the percentage of children born to a foreign mother almost doubled under Labour to 25 per cent.
This comes as an extra 500,000 children arrived in our primary schools and a similar number do not have English as their first language.
The report says even New Labour’s favourite think-tank, the Institute of Public Policy Research, acknowledged last year ‘that immigration under New Labour has changed the face of the country’.Sir Andrew said: ‘We would agree, the sheer scale of what has occurred is changing Britain fundamentally and irrevocably and in ways the majority of the population did not ask for, were not consulted about and did not wish to see.’
The MigrationWatch report estimates that 5.5million foreign migrants arrived in 13 years of Labour government, not accounting for those who left.
That is the equivalent of 423,000 a year – or 48 an hour. In recent years, the figure rose to around 470,000 per annum – close to one every minute.
Last night, Immigration Minister Damian Green said: ‘Unlimited migration has placed unacceptable pressure on our public services over the years.
‘That is why we are currently carrying out major reform of the system to reduce net migration to the tens of thousands.
‘We have already introduced an annual limit to the number of economic visas from outside the UK alongside new proposals to reform other routes of entry including student, marriage and settlement visas, which have in the past been subject to widespread abuse.’
Critics have insisted Labour adopted a deliberate policy of mass immigration to create a ‘multicultural’ country.
Last night, Labour’s immigration spokesman Gerry Sutcliffe said: ‘This is an unbalanced, misleading and highly political report. Migration levels increased initially because of the strength of the British economy over many years.
‘The most recent figures show net migration from outside the EU was coming down as a result of the points-based system and over a third of “long-term migrants” were in fact students, the vast majority of whom study, pay their fees, and then return home.’