Ministers accused of underestimating number of foreign workers by 400,000

The Government faced embarrassment over immigration after it emerged that 1.5 million foreign-born workers came to Britain in the past 10 years – almost twice its original estimate.

The numbers have been revised upwards twice in just 24 hours.

Peter Hain, the Work and Pensions Secretary, led a succession of apologies by ministers when he raised the estimate of overseas nationals taking jobs in Britain since 1997 from 800,000 to 1.1 million.

But that figure was thrown into doubt last night after the Conservatives released a parliamentary answer from July by Karen Dunnell, the National Statistician, suggesting the true figure was 400,000 higher.

She said: "For the three month period ending March 2007, there were 1.5 million overseas-born people in employment who had entered the UK in the past 10 years. This figure includes those who were children when they arrived."

Last night the Department for Work and Pensions said the 400,000 extra people were born overseas but are UK citizens.

Doubts also rose over a claim by Jacqui Smith, the Home Secretary, that 30 per cent of new jobs had gone to foreign migrants since 1997. In a clarification note obtained by the BBC, the Government indicated that 52 per cent of the new jobs had gone to foreign workers.

Chris Grayling, the shadow Pensions Secretary, ridiculed the confusion among ministers. He said: "This situation just gets worse; it's clear we simply can't trust the figures or statements put out by the Government on migrant workers in the UK.

"Ministers need to carry out an urgent review of how they handle this data and need to clear up once and for all how many people come to work in Britain."

Earlier, the Government faced anger from employers and unions and provoked a diplomatic row when it reimposed tough restrictions on Romanians and Bulgarians who want to work in Britain.

Strict controls placed on migrants from the two countries after they joined the European Union in January will remain for at least another year. Liam Byrne, the Immigration minister, confirmed that the limits would be retained because of "signs of a wider impact on public services" from those already in Britain.

Mr Byrne said he had spoken to both governments and understood their frustration. But he said: "I'm paid to go to work to do the right thing for the British national interest, and that is what I intend to do."

Low-skilled Romanian and Bulgarian workers are only eligible for a limited number of seasonal jobs in agriculture and food processing, a limitation that will remain until December 2008 at the earliest. They are barred from taking work in areas suffering jobs shortages, including transport and catering.

Self-employed Romanians and Bulgarians, as well as those deemed highly skilled, are free to accept jobs in Britain.

Critics yesterday accused the Government of attempting to court popularity among the voters.

Raduta Matache, Romania's acting ambassador to Britain, said she was yet to receive a "convincing explanation" for the decision.

She said: "This measure has a symbolic value more than a practical one. Great Britain has always taken pride in the flexibility of the labour market. It was considered one of the keys of the economic success of the United Kingdom. Why is this flexibility over for Romanians?"

Brendan Barber, the TUC general secretary, predicted that Romanians and Bulgarians would be forced into "bogus self-employment where they are more likely to face exploitation".

The National Farmers' Union has also called for the quotas on Romanians and Bulgarians seeking work on farms to be eased.

Business for New Europe, a pressure group representing many employers, also expressed disappointment. A spokesman said that Britain's generally open labour market towards EU member states such as Poland had boosted the economy.

The Institute for Public Policy Research, the left-leaning think-tank, condemned the extension of "this protectionist policy".

Danny Sriskandarajah, its head of migration, said it was a classic example of the "politics of migration" trumping Britain's economic interests.

How the chaos unfolded

* 18 July: Karen Dunnell, the National Statistician, calculates that 1.5 million people born outside the UK took jobs in Britain in the past 10 years. The figure is not released.

* 8 October: Peter Hain, the Work and Pensions Secretary, estimates that the increase in overseas nationals working here stands at 800,000.

* 29 October: Mr Hain apologises and says the figure should be 1.1 million.

* Yesterday 7.45am: Jacqui Smith, the Home Secretary, says sorry for the confusion over the figures.

* 6pm: Ms Dunnell's letter is released, putting ministers back on the defensive.