Downing Street has prevented the publication of a politically awkward cross-governmental report which found one potential cost of immigration is smaller than has been claimed.
The research suggests “displacement” – the number of UK workers unemployed as a consequence of immigration – is well below that claimed by ministers.
But this was considered potentially incendiary, Newsnight has learned.
The government declined to comment on the document.
Home Secretary Theresa May has previously used research from 2012 by the Migration Advisory Committee (MAC), a group of independent academics, as a basis for saying that “for every additional 100 immigrants… 23 British workers would not be employed”.
But the new analysis – by civil servants – is much less pessimistic. The work, an extension of that MAC research, estimates that the cost to existing British workers of new arrivals is much lower.
Officials say the prime minister’s team has prevented publication of the report, which has been ready since last year, to avoid igniting controversy.
Statistics released last week suggest the government is unlikely to meet its pledge to reduce net immigration to below 100,000 people a year by 2015.
If ministers wish to get tougher on new arrivals, research finding that immigration is easier to absorb than previously thought is politically unhelpful.
Immigration is also a coalition fault-line. Mrs May, a Conservative, has faced opposition to her plans to cut immigration from the Liberal Democrats.
Some Conservatives have also caused problems for her, too: David Willetts, the universities minister, has sought to prevent restrictions on foreign university student numbers.
Home Office officials protest that the new research, in parts, reflects an “institutional bias” in favour of migration among officials at the Treasury, Foreign Office and business department.
According to emails seen by Newsnight, the old research on displacement cited by Ms May was not considered sufficiently “robust” by either the Treasury or the business department.
The new report, however, has been checked by external academics and agreed across all the departments with a hand in migration – including the Home Office.
A government spokesperson said: “Reducing immigration so our economy delivers for people who want to work hard and play by the rules is part of our long-term economic plan… We don’t comment on internal government documents.”
Watch Chris Cook’s Newsnight investigation in full on Tuesday 4 March 2014 at 2230 GMT on BBC Two, and then afterwards on the BBC iPlayer and Newsnight website.