The Government is facing calls for the publication of an official report suggesting the impact of immigration is less than feared.
Ministers have repeatedly cited research by the Migration Advisory Committee that found 23 British workers are left unemployed for every 100 new arrivals.
But a study by civil servants has concluded that the 'displacement' figure is actually much lower, according to the BBC's Newsnight programme.
The report was apparently completed last year but has not been released amid concerns it could prove politically awkward.
Liberal Democrat MP Julian Huppert told Newsnight: "It's obvious that this report should be published as quickly as possible.
"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."
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."