By Ian Dunt
A report which would show immigration figures cited by the home secretary to be false has been withheld by Downing Street.
The report suggests the displacement of British jobs from immigration is much lower than figures regularly cited by Theresa May.
The home secretary has relied on a study, based on research by the Migration Advisory Committee (MAC), which concluded that 23 British workers are made unemployed for every 100 immigrants who arrive in the UK.
But emails seen by BBC Newsnight show civil servants did not believe the evidence used was "robust" and that a new report commissioned by the government - and reviewed by academics and experts - found the impact on jobs was far less.
That finding does not sit easily with government efforts to radially cut down on immigration and the report has now been withheld to avoid embarrassment for the prime minster and the home secretary.
Expert analysis of immigration on domestic work is mixed. While some domestic workers - particularly those in low-paid, low-skilled work - are undoubtedly affected by immigration, some research suggests immigration actually boosts domestic employment.
Some studies have found that industries with a higher amount of immigrant workers significantly increase productivity, thereby creating more jobs.
Others suggest that immigrants' need for housing and services boosts the local employment market.
It still appears that the new report will find some domestic jobs are displaced by immigration, although the figure is understood to be considerably lower.
The report is understood to have been ready since last year, but the prime minister's team stepped in to prevent publication.
Now that media pressure over its release has reached fever pitch, the report is expected to be released within the next few days.
The report also bolsters the position of Liberal Democrats in government, who have been trying to limit May's anti-immigrant policies.
They are joined by a handful of pro-immigration ministers who are concerned about the effect of a reduction on their department, such as David Willetts, whose university brief means he is critical of moves to restrict foreign students.
"It's obvious that this report should be published as quickly as possible," Lib Dem MP Julian Huppert told the BBC.
"We have to have the right figures, so we can make the right decisions, so that we get the best people here to help our economy."
Labour shadow immigration minister David Hanson said: "The British people should have information made available to them so they can make a judgement about the impact of immigration on jobs.
"This should be done on the basis of fact, not more empty rhetoric or spin from the government."
Home Office officials insist the research reflects an "institutional bias" towards more immigration in the Treasury and Foreign Office.
By Ian Dunt