Hussein al-Falluji, a Sunni member of the committee that drafted the constitution, said that his community would reject the document with their “dying breath”.

“We have never agreed on this constitution. We have objections which are the same as we had from day one,” he said. “This is an American constitution and we will not accept it, no matter what.”

Although the strident language could be dismissed as the frustration of a politician who did not get his way in the hours of tortuous negotiations, ordinary Sunnis seemed to concur. “This is a constitution written by exiles for exiles. It aims to exclude all those who participated in the events of this country in the past 35 years,” said Mahmoud Jubouri, 26, an engineer working in Baghdad who listened to the constitution being read out on television. “It was not written by professionals, but by Shia clerics and Kurdish dictators.”

The same sentiment was expressed by Abu al-Hakam al-Obeidi, a car dealer from the insurgent stronghold of Ramadi. He said that the constitution would split Iraq along ethnic lines and that the only reason that the document was being presented now was to satisfy a deadline imposed by America.

Central to their grievances are articles in the constitution that they regard as biased against them. For instance, many Sunnis were among the millions of former members of the ousted Baath Party, which included all teachers and other professionals. They fear that the constitution will bar them from senior government jobs.

The document also sets out a “federal” Iraq, where the capital, Baghdad, would lose much of its central authority to new regional powers in the Kurdish north and Shia south, which are in practice already breaking away from the centre.

The country’s huge oil wealth is concentrated in the north and south, leaving Sunni heartlands without important mineral reserves. Under the terms of the constitution, oil revenues would be distributed more equitably with the regions where the natural resources are found.

While the constitution states unambiguously that Iraq is a Muslim country, it also makes clear that for non-Arab citizens — shorthand for the Kurds — it is not an Arab nation.

Ordinary Sunnis might not be able to cite the specific wording of offending passages in the constitution, but they understand all too well the implications that it holds for their nation. For centuries the ruling class in Iraq, the Sunnis are being forced to face the fact that since the overthrow of Saddam Hussein they are no longer in control. The Kurds and the majority Shias, with the backing of the US military, are the new elites and the constitution will codify this change of power.

Baghdad, once the seat of Arabic learning and culture, will no longer have a central place in the Arab world, nor for that matter will it necessarily dominate Iraqi affairs. Shias in the south are building a mini-state with close ties to Iran, and Kurds in the north have created an autonomous region where many inhabitants have never visited the capital and do not speak Arabic.

The question now before the Sunnis is how to challenge this threat. If they mobilise their community and campaign for a “no” vote at the referendum they could legally destroy the constitution, should they win a two-thirds majority in three of the country’s 18 provinces. The Sunnis would then force fresh elections and begin the process of drafting a new constitution all over again, this time from a position of greater strength.

If they fail, and the constitution just announced is approved, there are fears that the Sunnis will increasingly support extremist elements in their community who are behind assassinations and bombings.

Times Recommends

• Michael Jackson: Not the final chapter
• Indian Army spends10m rupees on golf buggies
• Brüno toned down for 15 rating