EU talks: 'Crucial' day for possible Cameron-Tusk deal
British and EU officials are set for a "crucial" day of talks over efforts to renegotiate the UK's EU membership.
Downing Street sources said there had been a "breakthrough" on restricting benefits for EU migrants during talks between David Cameron and EU Council president Donald Tusk on Sunday.
But BBC assistant political editor Norman Smith said there was, as yet, no agreement on any of the UK's four aims.
Mr Tusk said "intensive work" would be needed during the coming hours.
The aim is to agree a deal to be put to EU leaders ahead of a summit on 18 and 19 February.
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An early deal, which would require the approval of all 28 EU nations, would allow Mr Cameron to call a referendum on the UK's EU membership before the summer holidays.
After their meeting over dinner on Sunday night, Mr Cameron tweeted that Mr Tusk had agreed to another 24 hours of talks before publishing the UK's draft renegotiation text.
'Watertight'
Mr Tusk, the former Polish prime minister whose council is comprised of the leaders of other EU states, tweeted: "No deal yet. Intensive work in next 24 crucial. #UKinEU".
After the 24-hour period has passed, negotiators will decide whether to table a draft agreement or not.
The BBC's assistant political editor, Norman Smith, said: "Although no final agreement has been reached on any of the four areas - immigration, sovereignty, competitiveness and protection for non euro countries - sources suggest this is because of the complexity of the deal and the need to make sure it is legally watertight.
"Number 10 suggests one of the main areas of dispute at the moment centres on plans to give the UK and other non-euro countries greater safeguards."
He said France, in particular, was unhappy with a British proposal to allow countries outside the eurozone to call a European Council meeting to discuss key issues affecting non-euro members, believing this would amount to a veto.
As part of his attempts to renegotiate the UK's EU membership, Mr Cameron has proposed denying in-work benefits to all EU migrants until they had been in the UK for four years.
He said stopping those migrants from claiming tax credits - income supplements paid to those in low-paid work - would reduce high levels of immigration to the UK.
EU leaders rejected this idea but suggested an "emergency brake" which the UK could use for up to four years.
The UK could use this to deny in-work benefits to EU migrants, but it would have to prove public services were under excessive strain and would need the approval of other EU states.
The proposal was to allow the UK to be able to impose the brake within three months of applying for it, but Mr Cameron wants it triggered immediately after the EU referendum. He also says there should be no time limit on its use.
A deal isn't a deal until, well, it's a deal. And there isn't one yet.
Donald Tusk's remarks on leaving Downing Street on Sunday appeared stark. "No deal," he said, to waiting reporters.
But a concrete deal on Sunday was always unlikely: with the next EU summit still over a fortnight away, there's still plenty of time for negotiation.
This latest calling point in the discussions was fuelled, we were told, by smoked salmon, fillet of beef and pear and apple crumble. Such sustenance didn't provide stamina for Messrs Cameron and Tusk to talk into the night: in less than two hours, Mr Tusk was gone.
But their teams continue to talk; a "crucial" 24 hours beckons, we are told. There could, though, be rather a lot of "crucial 24 hours" between now and referendum day, whenever that turns out to be.
After Sunday's talks, the prime minister's spokesman said: "Progress has been made in the past 48 hours, but we are not there yet."
He said the European Commission had tabled a text saying the UK meets the criteria for triggering the proposed emergency brake, describing this development as a "significant breakthrough".
This means Mr Cameron could deliver on his commitment to restrict in-work benefits to migrants for four years, he added.
Although the referendum does not need to be held until the end of 2017, it has been reported Downing Street favours a poll on 23 June.
Norman Smith said David Cameron hoped to "seize the moment" as he did not want the next two years to be dominated by the question and he wanted to take advantage of infighting in the "Out" camp amid reports that no Conservative "big beasts" were prepared to campaign for EU exit.
- Integration: Allowing Britain to opt out from the EU's founding ambition to forge an "ever closer union" so it will not be drawn into further political integration
- Benefits: Restricting access to in-work and out-of-work benefits to EU migrants. Specifically, ministers want to stop those coming to the UK from claiming certain benefits and housing until they have been resident for four years
- Sovereignty: Giving greater powers to national parliaments to block EU legislation. The UK supports a "red card" system allowing member states to scrap, as well as veto, unwanted directives
- Eurozone v the rest: Securing an explicit recognition that the euro is not the only currency of the European Union, to ensure countries outside the eurozone are not disadvantaged. The UK also wants safeguards that it will not have to contribute to eurozone bailouts
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