After a hectic series of meetings, Britain, which holds the presidency of the EU, postponed discussions until 9.30am today, just hours before formal negotiations with Turkey were due to begin.
Going into last night's crucial meeting, Austria was still blocking the start of talks, calling for consideration of a possible alternative to EU membership for Turkey. Such demands are anathema to Ankara, which first sought to join the bloc more than four decades ago.
During the course of a dramatic evening, the Foreign Secretary, Jack Straw, held a series of face to face meetings with his Austrian counterpart, Ursula Plassnik. Meanwhile Tony Blair spoke by phone to Austria's Chancellor, Wolfgang Schüssel, and the Europe minister, Douglas Alexander, called the Turkish Foreign Minister, Abdullah Gul, who was waiting to learn whether to make the journey to Luxembourg to start talks.
Germany, France and Greece all backed British efforts to launch the talks with Turkey today. But Austria continued to press for changes to the language of the negotiating mandate.
It remained unclear whether there was enough progress to clinch a deal. Asked about the prospects, a senior official replied: "God knows." As talks broke just after midnight Mr Straw said: "It is a frustrating situation but I hope and pray that we may be able to reach agreement."
Amid mounting tension, supporters of Turkey's accession argued that a rebuff to Ankara would provoke a crisis in the EU's relations with the Muslim world.
The Turkish Prime Minister, Recep Tayyip Erdogan, speaking at a resort outside Ankara, said Europe was at a historic crossroad. "Either it will show political maturity and become a global power, or it will end up a Christian club," he said.
"No EU decision will deviate Turkey from its course" toward further democracy and reforms, Mr Erdogan added. "We will, however, be saddened that a project for the alliance of civilisations will be harmed."
Asked if a deal could be reached, Ms Plassnik, replied: "I hope so. We will listen to each other, come towards each other in a good European spirit. " None of the main Austrian political parties backs Turkish accession. But despite his tough stance on Turkey, Mr Schüssel, appeared to have suffered a blow in regional elections in Austria yesterday.
Turkey has been knocking on Europe's door for decades, and has instituted a massive reform programme to get to the point of opening membership talks. Originally scheduled for this morning, the negotiations are now due to begin in the late afternoon.
However Mr Gul has made it clear that he will not make the journey to Luxembourg if the negotiating text is deemed unsatisfactory. Mr Erdogan phoned the Austrian Chancellor on Friday to make clear that second-class status was not acceptable to Turkey.
If they open today, the negotiations with Ankara will take a decade and at least two EU nations will have to hold referendums before giving Turkey the green light to join. Even starting the talks has proved highly controversial, despite all 25 member nations agreeing last December that they should begin today.
Since then the referendum "no" votes on the EU constitution in France and the Netherlands have changed the climate, and surveys show the majority of the EU population against Turkish accession.
Austria was seeking to delete a passage in the negotiating mandate which states that the objective of the talks is accession. Vienna's preference is for the inclusion of an alternative, "privileged partnership".
History ensures Austrians remain bitterly opposed
Across Europe, opinion may be divided on whether Turkey should be allowed to enter the EU. But in Austria there is little sign of a debate because history ensures that the issue touches the rawest of nerves.
In 1683 the Ottoman army of Kara Mustafa Pasha was routed at the gates of Vienna in a defeat that marked the last Turkish effort to take the city. All around the Austrian capital are reminders of the battle and so strong is the event in the national consciousness that newspapers have characterised Ankara's EU bid as a new siege of Vienna.
To complicate matters further Austria is a strong supporter of (Christian) Croatia, which also wants to join the EU. This step has been held up because of a row over Zagreb's lack of co-operation in surrendering a suspected war criminal, Ante Gotovina.
Austrians feel it would be wrong to start talking to Turkey while holding back on Croatia. Vienna's critics suggest darkly that Austria's own past may prompt it to worry less about punishing war crimes than other nations.
Taking a tough stance has proved politically popular for the Austrian Chancellor, Wolfgang Schüssel, but his party was crushed in regional elections yesterday.
Elsewhere in Europe, the echoes of history have played a part in the debate. France, home to Europe's largest Armenian population, has sometimes had difficult relations with Turkey. In 2001 its parliament formally recognised the Armenian genocide (during the collapse of the Ottoman empire) provoking fury from Ankara.
Ironically Ankara's biggest rival, Greece, has not sought to hold up talks, believing that a Turkey inside the EU would be more modern, restrained and susceptible to outside influence.
Stephen CastleReuse content