David Cameron has emerged from a "heated" EU summit hailing the first steps towards re-negotiating Britain's relationship with Europe and thwarting European leaders who wanted Britain to take refugees from the Mediterranean.
In a press conference ending two bruising days of talks in Brussels, the Prime Minister claimed a victory in kicking off the behind-closed-doors technical work that will lead to what he called a "substantial package of reform".
Mr Cameron also defended using an opt-out so not to take some of the 150,000 migrants who have arrived in Europe after fleeing Africa and Syria, a move that prompted fury among other European leaders.
But the summit risked being marred after a leaked memo suggested the Prime Minister's tactics on re-negotiation are founded on arguing Britain will “ultimately vote for the status quo” at the in-out referendum, which will take place before 2017, because voters will be warned of the "risky" alternatives.
The memo, reported by The Guardian, also claims Mr Cameron is not pushing for a change of the Lisbon treaty before the vote - a revelation that had already angered Eurosceptics last night.
David Cameron, right, speaks with Italian Prime Minister Matteo Renzi during a round table meeting at an EU summit in Brussels
Despite fellow EU leaders being more concerned with the migrant crisis and Greece's financial troubles, Mr Cameron told journalists how his "priority" was to start the process of re-negotiating the limits the EU places on Britain - and said sovereignty, fairness, competitiveness and immigration were his four priority areas.
He argued the EU "interferes too much" and Britain does not want an "ever-closer union .. dragged into a state called Europe".
"It may be for others but it never will be for Britain," he said, and went on to outline the "flexibility" he craves where the "single market and EU works for all".
"At this summit my aim was to kick off the technical work on all of these issues and the specific reforms in each of those areas," he said, adding the discussions will take "tenacity and patience". "I'm confident we can agree the substantial package of reform."
On refugees, Matteo Renzi, the Italian Prime Minister, reportedly lashed out at his counterparts for refusing to accept migrants.
"If that's your idea of Europe, you can keep it," Italian sources said, according to The Telegraph. "Either give us solidarity or don't waste our time.”
But Mr Cameron, who conceded there was a "heated and quite lengthy debate", said he was "very insistent" that re-locating migrants who have already arrived is "counter-productive", and renewed the Government line that the key to solving the crisis was to "break the business model" of the people smugglers.
He added that is "not to say we won't play our part", pointing to Royal Navy rescue missions, intelligence gathering and the foreign aid budget.
"Others have decided to go ahead but we are under no obligation to join them," he said of refugee quotas.
Downing Street officials admitted during the summit that getting all 27 other EU nations to ratify changes to the Lisbon treaty, which underpins the union, will not be achieved ahead of the referendum.
Instead, the British Government wants to secure binding agreements with member states which can be attached as a protocol to the treaty the next time it is ratified - potentially in another 10 years.
Reports have emerged in the last month suggesting there was insufficient time to get every country to agree to the UK's demands before the vote, and it was confirmed on Thursday night to the BBC.
Back in the UK, the disclosure prompted anger and criticism against broken promises over Europe in the past and fears other countries will be cool on offering binding deals if there is a prospect Britain then withdraws.
Mr Cameron did not deny the memo's existence when questioned by journalists and said he wanted to make a "wholly positive" case for the UK to remain in a reformed EU. But he was clear he did not rule anything out if he did not get the deal he wanted.
He said his approach was not to "kick the tables in and making immediate demands" but to make clear where changes were needed in both the UK and Europe's interests.
"People can see that Britain has got a legitimate set of questions, a legitimate set of asks and that people can see that there is a really deep and sensible thinking behind this," he said.
Asked about getting the reforms embodied in treaty changes, he said it was "never the case" that he believed that this would be possible by the time of the vote - though in January he said he would be demanding "full-on treaty change".