A map today reveals parts of Britain where more than half of jobs are held by workers who were born overseas.
The workforce in large parts of London is dominated by people born abroad–despite Labour’s repeated promises to deliver ‘British jobs for British workers’.
But foreign-born employees also have a strong foothold in other British towns and cities, from Slough and Reading to Manchester.
Campaigners said the focus of employers and Whitehall should be on finding jobs for the young Britons out of work in many of these areas.
And last night, immigration minister Damian Green said: ‘This shows why we need a limit on work visas as well as a better trained British workforce.
The most startling figures, based on information from the Office for National Statistics, relate to Newham–the East London borough hosting the 2012 Olympics.
Here, almost seven in every ten jobs are filled by workers who were not born in the UK–or 65,100 out of 93,700 posts. Many of the jobs are on the Olympic site itself.
The number of British-born people in Newham who are not in work is 25,600. This is a combination of the unemployed and those classed as ‘economically inactive’, such as students and the long-term sick.
There are six local authority areas where more than 50 per cent of the jobs are filled by migrant workers–and a further 18 where those born outside the UK take up more than one in every three jobs.
Outside London, the areas where the biggest proportion of jobs are taken by immigrants are Slough, Leicester, Luton, Reading, Cambridge, Manchester and Oxford.
Crawley, in West Sussex, and Elmbridge, in Surrey, are also at the top of the list.
Many overseas workers in places such as Slough and Reading are Eastern Europeans who do not need work permits.
Experts say this makes it more important for the Government to impose a strict cap on non-EU migrants in an attempt to bring the total number of foreign workers under control.
The coalition unveiled an interim cap this week, along with a plan to make employers provide non-EU migrants with private healthcare to ease pressure on the NHS.
The final level of the cap will be decided later this year.
Alp Mehmet, of MigrationWatch, said: ‘Where there are gaps in the UK labour market we should be filling them from the UK population.
‘There is a laxness and a looseness about the way people are allowed in. What we want is closer control.’
The area with the smallest proportion of foreign-born workers is Newark and Sherwood, in Nottinghamshire, at 1.5 per cent.
Under Labour more than 1.1million jobs–half the total created–were taken by non-EU immigrants requiring work permits, according to the independent House of Commons Library.
In October 1997, British-born workers made up 92.5 per cent of the workforce. By 2009, this had fallen to 87.1 per cent.