Member states gain time in UK talks

In a paragraph added to the conclusion of the EU summit, leaders simply said they "agreed to work closely together to find mutually satisfactory solutions in all the four areas at the European Council meeting on 18-19 February 2016."

The four areas in which Britains seeks reforms are economic governance; competitiveness; sovereignty; and immigration.

The formula left open the possibility of a limited treaty change in the future.

"The good news is there is a pathway to an agreement," British prime minister David Cameron said at a press conference.

"But the truth is this: it will be very hard work," he added. "We're attempting something very difficult that hasn't been tried by another country."

Leaders from all sides appeared to be careful not to jeopardise the process of the negotiations and chose to give more time before really deciding in which direction to go for an agreement.

"They sort of gave a green light to the experts to explore all options," an EU official told EUobserver, suggesting some time will be needed to define the main lines of a future agreement.

"I think you should not expect a document until very shortly before the February summit," the source said.

As a consequence, there was no breakthrough on the issue which is considered as the most difficult: the four year ban on benefits for EU citizens in the UK.

The proposal "remains on the table," Cameron said.

The British PM inisted that the European Commission, which has been tasked to work on a deal proposal with the UK, "believes there is a solution".

But a majority of member states remain opposed to the proposal, which would, some say, introduce discrimination between EU citizens.

"We have to be tough when it comes to some red lines," Tusk warned. He added that "no one, including Cameron, is ready to accept discrimination."

His remark was echoed by German chancellor Angela Merkel and French president Francois Hollande, who both made clear that a deal would have to respect the principles of the EU.

Cameron also reminded that for him, "what matters is that change is legally binding and irreversible."

"That was discussed, and there is a good way through that," he said

In her press conference, Merkel confirmed that "what emerged clearly is that we need treaty change."

"That might be possible but that might happen later," she said. "We have to pave way for successors to be able to go on and further develop what we decide today."

A solution on that matter could be what a EU source called the "Edinburgh solution", refering to an agreement at an EU summit in the Scottish capital in 1992, when Denmark was granted exemptions in several fields so that it could ratify the Maastricht treaty and stay in the Union.

A promise could be made to the UK that a change would be introduced when the EU treaty needs to be amended, for example when a new country next enters the EU.

It would not be a full treaty change requiring an intergovernemental conference and ratification process, but it might give satisfaction to the UK.

The discussion over a dinner of chicken, venison, and marinated oranges was "frank and open," Hollande said, using the diplomatic formula for a lively debate.

"It was a very substantial discussion, going into real detail of all the areas that I put forward," Cameron said.

Cameron "reiterated the openness to alternative solutions only if they could achieve the same objective," Tusk said.

As for the other leaders, Tusk added, they "voiced their concerns, but also demonstrated willingness to look for compromises."

Apart from the so-called "fourth basket" - the immigration item on the British list if reforms, which includes benefits cuts - concerns were raised about the role of national parliaments in EU law-making, and about relations between eurozone and non-eurozone countries.

"I'd like to warn you against the illusory impression that there are three easy questions and one tricky one," European Commission president Jean-Claude Juncker told reporters.

"There are four tricky questions. Each one covers further questions on which we'll have to back until February," he said.