A furious row has erupted between European leaders over who will take 40,000 migrants who crossed the Mediterranean to claim asylum.
The United Nations called on Britain to accept its share of thousands of people who have fled North Africa, after a Brussels summit was dominated by arguments over where the migrants should settle.
Matteo Renzi, Prime Minister of Italy where most of the migrants have arrived in Europe, tore into other leaders telling them that if they did not agree to share the burden 'you aren't worthy of calling yourselves Europe'.
Around 60,000 people have arrived in Europe from north Africa so far this year, while 2,000 are estimated to have died while making the dangerous journey.
David Cameron has ordered a more targeted approach to tackling the problem, beyond 'plucking people out of the sea'.
But he has vowed to use a British veto to opt out of any EU-wide plan to spread 40,000 migrants across the continent.
Peter Sutherland, special representative of the UN secretary-general for international migration and development, said it was wrong for some countries to turn their back on the plan.
He told BBC Radio 4's Today programme: 'All member states should participate in the voluntary settlement, including Britain, Ireland and Denmark.
'This is a question basically of European solidarity. Why should Greece and particularly Italy take this unfair burden of responsibility for people who are refugees escaping from persecution?'
He said providing ships to rescue migrants found at sea was 'not enough'.
Leaders have agreed to relocate 40,000 migrants from Italy and Greece to other EU countries over the next two years, in an effort to share the burden of a growing crisis.
They also agreed to resettle another 20,000 refugees from Syria and Iraq.
Italy wanted a quota system to be created to fix numbers of migrants to be sent to each country, but after facing criticism from other countries plan will now be voluntary.
A working dinner in Brussels continued into the small hours of this morning as leaders failed to agree on how to tackle the crisis.
Mr Renzi turned on Hungary, Poland and Lithuania, whose leaders say they won't be forced to take any.
He told them: 'If you don't agree on 40,000, you aren't worthy of calling yourselves Europe'.
In what was described by diplomatic sources as an 'emotional' outburst, he then said pointedly: 'If that's your idea of Europe, you can keep it'.
Now member states will have to agree on how many asylum seekers they are willing to take by mid-July, but it will be voluntary not mandatory, much to the anger of Italy, who receive the bulk of the migrants.
Mr Renzi said afterwards the outcome of the meeting fell short of what Italy needed. 'Relocation is a first step but for us this is not the solution to our problems.'
Britain has already said it will use its veto to avoid taking any of the migrants, and around 12 other states, many from eastern Europe, are also opposed to taking a set number.
Last week Theresa May called for the migrants crossing the Mediterranean to be forcibly sent back to Africa as a deterrent and to show there was 'no merit' in coming to Europe.
Figures released last week revealed that 100,000 migrants have made the crossing from North Africa to southern Europe since January alone, with 57,000 landing in Italy.
An estimated 170,000 migrants reached Italy by sea last year. But only a third of them claimed asylum there, with the rest likely to have headed for northern Europe, including Britain.
EU officials last night tried to diffuse the row and claimed that the talks were a success because a total of 60,000 migrants in Italy and Greece - 40,000 who came by boat and 20,000 from Syria - would be resettled.
A European source said the EU's two top figures, European Council President Donald Tusk and European Commission chief Jean-Claude Juncker, had clashed at the meeting but the two rejected the suggestion.
'Don't believe those who are tweeting, leaking info. Whenever we have difficulties, we discuss these things between ourselves,' Mr Juncker said at a press conference.