European Union migrant cap plan illegal, says Nick Clegg
Nick Clegg has condemned leaked Home Office proposals to cap the number of European Union immigrants at 75,000 a year as "illegal and unworkable".
The deputy prime minister said it would damage the economy and mean reprisals by other member states.
Home Secretary Theresa May said she was "not proposing to introduce such a cap now" but there was a "possibility of reform in the future".
There was growing concern over "abuse" of free movement in the EU, she added.
The report of the leaked Home Office paper in The Sunday Times suggested Mrs May wants to introduce a cap on immigration from the EU, at about 75,000 a year. In the year to June 2013 183,000 people from the European Union moved to the UK.
The changes would mean professionals and highly skilled migrants from wealthy countries such as Germany, Austria or the Netherlands could move to the UK only if they had a job offer, and lower-skilled workers would be allowed to settle only if they were employed in posts where there was an identified shortage.
On BBC Radio 4's Today programme, Mrs May declined to comment on the leaked report, but spoke of the "overall issue of free movement".
She said: "It's something I've been talking about with my opposite numbers - interior ministers in other countries within the European Union - for some time now.
"There is a growing concern not just here in the UK, but elsewhere too, about the abuse of free movement, about the way in which people can move freely across Europe, sometimes for access to benefits."
The UK is tightening up rules on migrants' access to benefits, as Romanian and Bulgarian nationals lose the last restrictions on their rights to work in the country from next month.
But Mrs May said she and Prime Minister David Cameron wanted further changes to control the access of nationals of any future EU entrants.
She told Today: "What both the prime minister and I have said is we need to look at this and think about whether that should be longer, whether it should be more flexible, whether we should look at restricting free movement rights until a country's national income, GDP, is at a certain level, so we are not looking at the great disparities we sometimes see across the EU.
"What I'm saying is that, as we look ahead to the whole issue of reform of the European Union, I think we do need to look at this question of free movement."
But, speaking at his monthly press conference, Mr Clegg said: "My advice to the Home Office is to spend less time leaking policies that are illegal and undeliverable and spend more time delivering on the policies that we have agreed as a coalition government, notably the reinstatement of exit checks."
He added: "If we pulled up the drawbridge now and said to German lawyers, or Finnish engineers or Dutch accountants that they can't come to work, it would be a disaster for our economy.
"We are an open economy. The City of London would grind to a halt overnight. It would be very, very bad for British business and the health of the economy."
The deputy prime minister also said: "It would be very unwelcome to the two million or so Brits who live and work abroad, who I don't think would thank the Conservative Party for entering into a sort of tit-for-tat race to the bottom, where everybody across the European Union starts pulling up the drawbridge and not allowing people to move to look for work in other parts of the European Union."
Asked about Mr Clegg's comments when she faced the Commons Home Affairs Committee, Mrs May replied: "I'm not proposing to introduce such a cap now. What I'm talking about is the possibility of reform in the future."
She added of Mr Clegg's words: "That statement has an assumption within it."
Mrs May also said: "He has, as I understand it, made a statement on the basis of, if we were going to do this now, this is what the situation would be. I'm not proposing to do it now. I'm talking about potential reforms of accession treaties in the future."
A spokesman for European Council president Herman van Rompuy suggested most of the migrants coming to the UK did so to work, while many Britons emigrating did so to retire and arguably could be "a bigger burden".
"It is not one-way traffic by any means," Richard Corbett, a former Labour MEP, said.
Free movement within the EU could only be altered through a treaty change, he added, but there were other "smaller things" the UK could do within the current legal framework.
Last month, Mr Cameron announced a range of measures to restrict some rights to benefits for some people from EU countries in the UK.
At the time, European Employment Commissioner Laszlo Andor described the proposals as "an unfortunate over-reaction", adding that EU rules applied equally to all 28 member states and had been agreed to by the UK, which risked looking "nasty".
Many Conservative MPs have urged Mrs May to defy the EU and extend the transitional controls on Bulgarians and Romanians.
But Labour leader Ed Miliband said what was needed was not "leaks and half-baked proposals" but "real measures to reassure people over immigration" - such as action on enforcing the minimum wage and requiring firms to advertise jobs in the UK.
Shadow home secretary Yvette Cooper said: "This phoney war is irrelevant to the government's removal of transitional controls (on Bulgarians and Romanians) in January.
"Theresa May and Nick Clegg are having a row with each other to distract from the fact that they haven't put measures in place to manage the lifting of transitional controls in January."
UK Independence Party leader Nigel Farage called the leak of the Home Office document "comical", adding: "The government simply cannot impose a cap on migration from the EU under EU rules. That is a fact.
"The only way to achieve this would be to leave the European Union. Yet Cameron has already very publically stated he does not want to see happen."