On the eve of its expansion from 15 to 25 countries, the European Union is tightening up immigration policies for fear of an uncontrollable influx of migrant workers. But with its aging and dwindling workforce, western Europe needs more outsiders to fill available jobs, and the marketplace is finding ways to do that, albeit not legally.

In the heart of Brussels, the Canal de Charleroi runs through blocks of dismal factories and abandoned warehouses. It's still cold out, but that doesn't deter the illegal immigrants who come here in search of work. With hands in pockets and shoulders hunched, they wait for a car to pull over and offer them a day's work. There are Ukrainians here, Russians and Romanians. On one corner where the Africans gather a car pulls over and the men flock around it. Did the driver offer anyone a job?

"I don't know, he had been drinking, he wants to play with us, there are people like that," said an African laborer. "Most the time, there is no work. Look there are over 100 people here, but only two or three of us will work today. It doesn't pay well. Maybe 25 or 30 euros a day."

For these people without papers, there isn't much of a support network here. The only social worker for the area is Yann Malebeek and he worries about them.

"It's pretty dangerous because you don't know what kind of person you go with, you just step into a car with somebody. A car just stops and points out a finger like two persons and they just jump into the car," he said.

The would-be employers flee from a reporter's microphone, but Abdellah, an illegal worker standing on the Moroccan corner, was willing to speak about his experience with them.

"An employer who takes a risk by employing someone without papers -- why does he do it? Not because I work better than someone else or am more competent but because I am the cheapest, the most obedient and always say yes.. and when it doesn't work I can be thrown out like a dustbin bag," he said.

Many of the illegal immigrants turn to the church to ease their isolation and seek solace. The church also provides a network for people in the same situation looking for work. In Brussels, churches offer meetings in a variety of European languages. This Sunday the Polish church is packed with young men.

Different nationalities sit at tables nursing endless cups of coffee, while a video about Jesus plays constantly. But not everybody here is an illegal immigrant. Elena has a good job at the European Parliament and comes to the Christian coffee house as a volunteer.

"A lot of Belgians exploit them," she said. "A lot of diplomats exploit them and they are the ones who make laws against them.... with their nannies that they don't pay properly."

With the European Union on the brink of enlargement, many EU countries have decided to limit the influx of foreigners, despite obvious labor shortages. But in a January visit to the European Parliament, U.N. General Secretary Kofi Annan called for Europe to change the rules.

"I look forward to the day when Europe rejoices as much in the diversity within states as it does in diversity between them. Migrants need Europe but Europe also needs migrants (applause). A closed Europe would be a meaner, poorer, weaker, older Europe, an open Europe, fairer, richer, stronger younger Europe, provided you manage migration well," he said.

Despite the standing ovation, Roger Helmer, a British Conservative member of the European Parliament who is known for his opposition to immigration, says it's presumptuous of Mr. Annan to lecture Europeans on immigration.

"The idea that we can cut the population and replace it with people from very different foreign cultures is something I think a lot of people would feel very uncomfortable with," he said.

In Europe, migration remains a divisive and emotional issue. But demographer and European Council Adviser Jerry Koomans stresses that Europe needs foreigners to come to live and work.

"We have to learn to deal with the society we have, which is an aging society," he said. "We don't have the labor supply we had before. We need more workers. We have to speed up the awareness of the problem in terms of economic growth, look at what the U.S. is able to do compared to us. High immigration is part of their dynamism and if we did the same it could be part of our dynamism as well."

But, as the busy market for day laborers at Brussels' Canal de l'Rois shows, people are already on the move, trading in their economic uncertainty at home for a chance of a better life elsewhere.