By David Loyn
Developing world correspondent, BBC News
The true scale of the refugee exodus from Iraq is impossible to calculate, but the United Nations refugee agency (UNHCR) says that during some periods this year it has run as high as 100,000 a month.
Raad Ibrahim says he was forced out of his home by Shia militias
This is the biggest movement across borders in the world at the moment.
Iraqis form the largest group among asylum seekers reaching Europe, and are putting huge pressure on their neighbours - particularly Jordan and Syria.
The numbers fleeing abroad went up significantly after the destruction of the golden-domed mosque in Samarra in February.
Whoever caused this outrage, it had the effect of sparking the worst round of sectarian violence that Iraq has seen.
In a small flat in a poor area in Amman in Jordan, I met Raad Ibrahim. He is a Sunni, but his wife is Shia.
Like much of Baghdad their home was in a place where such distinctions have never mattered until now.
Raad said that they left Iraq after Shia militias came threatening to shoot him if he did not hand over his house.
He had already lost his car showroom to the Americans, and had other business interests commandeered by militant groups.
Kidnappings and targeted killings force some families to flee Iraq
To make the journey to Jordan, he and his family drove overland, a perilous journey across the huge wasteland of the desert in Anbar province.
Many refugees have not even made it as far as the border since cars and buses are routinely targeted on the road.
But those who run have weighed the risks and judged that even the dangers of this road are not as bad as staying in Baghdad.
Apart from the daily threats from militias, and the increasing sectarian conflict, kidnapping has now become commonplace.
There are some reports suggesting that kidnapping is now a self-financing criminal activity, and many of those involved have no contact with the insurgency.
Even those who are insurgents see kidnapping as a commercial activity, designed to support their militant activities.
One kidnap victim, who agreed to talk to the BBC providing we guaranteed to protect his anonymity, said that some of the gang holding him were religious extremists supporting al-Qaeda, and others were Saddam supporters.
This is further confirmation that the Sunni insurgency has formed alliances between these two groups.
But they made it clear that the aim of the kidnap was to raise funds for the insurgency.
The man was not rich, and said that his family would never be able to pay the $40,000 (£20,000) demanded.
During the days that he negotiated the figure down to something his family might be able to pay, the kidnappers at one point suggested that he might like the "honour" of becoming a suicide bomber, although he was a Shia, and this would have meant blowing up Shias.
"They said if God wants to guide you, you can sit in a car, and do the operation. It would feel just like a pinprick."
With mass kidnappings now an increasing feature of the conflict, particularly from the Shia side, the sectarian militias and insurgents who now have the upper hand in Baghdad have become increasingly bold.
They are also carrying out more targeted assassinations.
In Jordan I met an Iraqi doctor, who was also unwilling to give his name.
He said that he had always wanted to stay in Iraq, and stayed even after his daughter was injured when a suicide bomber killed himself near her school.
Some of her classmates were killed.
The incident that pushed the doctor into taking the decision to go was when his name appeared on a list of people who were targets for assassination.
He said that now was not a time to make a stand since he would be likely to die.
"Losing a life, being a hero at this time is wrong. It is not a time to be shot by a silly bullet or shell."
Shortly after he arrived in Jordan, I asked him for his impressions of what is happening to Iraq.
"It's the worst that can happen to any nation. It's very surprising how the people changed in those three years.
"We used to live as neighbours all together -Sunni, Shia, Christian - and suddenly this sectarianism came out of I don't know where."
The problem for Iraq is that the more of its key citizens that it loses - doctors, teachers, business people - the worse it will become for those who remain.
Iraq will be left vulnerable to the gunmen.