Britain secured a number of key demands at the European Union to boost jobs and growth across the continent, Prime Minister David Cameron said today.
Mr Cameron declared himself frustrated yesterday that the priorities of a group of 12 EU states, including the UK, had been ignored in the draft communique for the European Council summit in Brussels, in favour of proposals from France and Germany.
But as the summit ended today, he said they had "made our voice heard" and secured "fundamental" change on issues ranging from trade to energy and completing the single market.
Mr Cameron said he had forged an "unprecedented alliance" at the EU in favour of open markets and trade, which included not only the UK's traditional allies in Scandinavia but also major southern states Italy and Spain.
He said: "Today in Brussels we have made our voice heard. The communique has been fundamentally rewritten in line with our demands."
The main business at today's summit was a ceremony in which 25 EU countries signed up for a new "fiscal compact" to restore stability to the single currency area.
Mr Cameron and his Czech counterpart sat it out - the only two EU leaders not to be endorsing a deal designed to impose stronger financial discipline on the eurozone, with sanctions for those countries breaching debt and deficit limits.
European Commission president Jose Manuel Barroso said afterwards: "In the eyes of the world, what is at stake is the very credibility of the euro area and of Europe as a whole: its ability to deliver sustainable fiscal consolidation, growth and employment.
"The euro is not just a currency of some countries, the euro is the currency of the European Union.
"Through their formal commitment at the treaty level to increase discipline and convergence, the member states are showing that, from monetary union, we are now progressing towards a true economic union."
But Mr Cameron made clear that his priority for the summit was securing real action to complete the single market, boost trade and stimulate growth.
He detailed the changes made to the communique this morning which he believes will help achieve these aims.
"There was in the original communique no mention of deepening the single market in services," he said. "Now we have a clear commitment to take action in that area.
"There was nothing on tackling regulated professions and properly opening up this vital element of the single market. Now we have a clear commitment to make progress on that specific area.
"There was no reference to deregulation. Now we have clear references, including sectoral targets, a timetable and targeted action for micro-enterprises - those firms that employ less than 10 people.
"There was no mention of completing the internal energy market. This is a change that can add several percentage points to EU GDP. There is now, in the communique, a specific deadline to achieve this by June 2014.
"There was, incredibly, no mention of trade - one of the great drivers of economic growth. Now there will be a special focus on trade, including trade deals, at our next meeting in June."
He added: "This was not just a British initiative. We were joined by a strong group of leading countries, all of whom spoke up very strongly at the Council, at the dinner last night, and again at the meeting we had this morning.
"I would say that for the first time since we've been setting out these ideas, our letter really did become the agenda for this European Council.
"We now have a plan that we must stick to in the months ahead. We have the words, now we need to make sure we get the actions that follow from those words."
The Action Plan for Growth in Europe was signed by the leaders of the UK, Netherlands, Italy, Estonia, Latvia, Finland, Ireland, Czech Republic, Slovakia, Spain, Sweden and Poland.
Mr Cameron said this amounted to an "unprecedented coalition which brings together countries from all four corners of the EU", representing more than half the population of the bloc.
Unemployment figures released yesterday, which showed that more than 24 million people across the EU are looking for work, were "a stark reminder that we need to recover Europe's dynamism and create jobs", said Mr Cameron.
Herman van Rompuy - who was elected unopposed for a second term as European Council president last night - said that today's fiscal compact would help boost jobs and growth.
Addressing the 25 signatories, Mr van Rompuy said: "By signing, all of you commit to bring a strong fiscal rule into your national legislation, preferably at a constitutional level. It will have binding effects and a permanent character."
The president of the European Council said the stronger economic "self-constraint" enshrined in the new accord would help prevent a repetition of the sovereign debt crisis: "It will thus also reinforce trust among member states, which is politically important as well.
"The restoration of confidence in the future of the eurozone will lead to economic growth and jobs. This is our ultimate objective."
Mr Barroso said: "Contrary to all the negative prophecies about the future of the euro, and even of the EU, this agreement, with its binding rules in terms of reinforced governance, signals the irreversibility of the euro and a very important step forward in European integration."
He said the new Treaty on Stability, Co-ordination and Governance in the Economic and Monetary Union represented "the very culture of financial stability that is a prerequisite for true economic union".
He added: "I am convinced that the member states and the EU institutions are now in a much better position to complement these indispensable efforts on fiscal responsibility with further reforms for competitiveness and increased solidarity."
The 15-minute signing ceremony marked the end of months of effort to calm fears over the euro's fate.
The resulting treaty or "fiscal pact" was forged after Mr Cameron dramatically vetoed plans last December for a 27-nation treaty change to beef up eurozone discipline.
Mr Cameron denied the EU was usually a "Franco-German stitch-up" and insisted Britain remained "one of the bigger players" around the table.
"I don't see the EU, as you put it, as a 'Franco-German stitch-up'. What I see it as is an organisation of 27 countries where clearly the bigger players, of which Britain is one, have a large influence but when you work together with like-minded allies, particularly when you can include allies from unexpected quarters - the fact that the Italians, the Spanish, the Portuguese and others are now supporting this approach - you make a real difference," he said.
The Prime Minister welcomed the fact that the "air of crisis" over the single currency that had dominated recent summits had been dispelled.
"The euro still faces some big challenges but there hasn't been an air of crisis," he said.
"There has been an air of let's get on and do things that will help the European economy to grow."