Home Secretary Theresa May is due today to give the full details of a cap on skilled workers from outside the European Economic Area allowed into the UK. Controversially, the government’s cap will not include employees transferred by their companies from another country if their salary is more than £40,000.

During the election campaign, David Cameron pledged to cap immigration levels, while his then Lib Dem rival Nick Clegg – now his deputy – said that policy ignored the fact that most immigration came from the EU. Last week the government’s migration advisory committee recommended a cap of up to 43,700 which would mean that the number of migrant workers coming to the UK from outside the EU would be cut by between 13% and 25% next year.

BBC political editor Nick Robinson said tense talks between the Tories and Lib Dems had resulted in a compromise.

Last year 50,000 visas were issued for tier one (highly skilled) and tier two (skilled) workers from outside the European Economic Area (the EU plus Iceland, Norway and Liechtenstein). Of those, 22,000 came on intra-company transfers.

Nick Robinson said a consultation on cutting the number of non-degree level students coming to the UK – due to be published soon – had not yet got cross-coalition agreement. In the new year, ministers will produce proposals to reduce the amount of family members who can join immigrants already living in the UK: “The Conservatives pledged to get immigration down from hundreds of thousands to tens of thousands per year. To do so they will have to persuade their coalition partners to back major cuts to other immigration routes”

Sir Andrew Green, of the Migration Watch think tank, informed BBC Radio 4’s Today programme: “It’s a small reduction, but don’t forget the 50,000 is much lower than it has been in recent years… It’s a reduction from a low figure, we regard that as a sensible outcome with a modest total.”

He said the cap focused on “those people who employers actually need” and would reduce the number of people who “come on spec, hanging around looking for a job” and the minimum £40,000 salary would make a “big difference”.

He added: “This is the first time in British history that any government has set a broad policy objective for net migration and we have to do that. We must reduce immigration – our population is heading for 70 million in 20 years, 68% of that, more than two thirds, is down to immigration.”

David Frost, director general, of the British Chambers of Commerce, said it was important that changes to migration policy did not harm British business: “Clearly the government has a mandate to bring down net immigration but at a time when we are trying to squeeze every bit of growth out of the economy, changes to migration policy must not harm UK competitiveness.”

He said global businesses “must have the ability to bring their skilled employees across the globe into the UK”.

Committee chairman Professor David Metcalf said the number of visas for skilled workers issued under what are called tier one and tier two needed to be between 37,400 and 43,700 for 2011/12.

This would represent a cut of up to 12,600 from 2009, he said, although this did not allow for the government’s planned exemption for intra-company transfers.

The advisory committee said that even this would contribute only 20% to the government’s target of reducing UK immigration from hundreds of thousands to “tens of thousands”. The other 80% cut would have to come from student and family migration.

Keith Vaz, Home affairs select committee chairman and Labour MP, said he did not believe the cap on skilled migrants would work: “There are going to be so many exemptions, from the education sector to elite scientists to football players to business, that there are going to be so many holes… that it actually won’t be a cap at all,” he said.