Every morning the same ritual takes place at Plaza Eliptica, in the south of Madrid. Dozens of construction workers are waiting for the builders’ vans to arrive. The vans bring foremen who are looking for black market workers for the day.

Only some of those waiting will be given the chance to get into the vans. They’ll then be driven straight to the building site.

The labourers here are all immigrants. Many have no papers, like the man we met, who says he arrived in Spain a year ago: "You work an hour here, a couple of hours there. Which means you earn 15 or 20 euros now and again. That’s better than nothing."

The crisis has caused a boom in the black market, in a country where it’s already a big part of the economy at the best of times. Twenty percent of Spain’s economic activity is spiralling out of control.

By comparing different indicators, like the rate of unemployment and the number of those signed on to social security, experts calculate that some 80,000 people have gone onto undeclared income in the past twelve months alone.

Social dumping

The situation is sparking tension, particularly in the building sector. Unemployed Spanish workers are furious. Emilio, a tile-layer who’s been out of work for several months, says that these practices are hindering him from getting back into the job market.

"They work for half the wages we do," he explains. "They’re given 15 euros and a sandwich for the day’s work. And the immigrants do it, they agree to work for that. I’m not against them, I’m not racist. But I want to be able to make a living in my own country too."

Back at Plaza Eliptica, at 6.30 in the mornig, it's rush hour. We’ve been able to shoot some transactions with a hidden camera. An employer is making a worker sign some papers. The workman realises that the so-called contract is unrelated to the labour he’s being hired to do. Voices are raised, but the labourer ends up getting into the van anyway.

Paco Martinez, of the UGT trade union, is appalled by the exploitative methods used by these unscrupulous employers. He says many of these workers don’t even get their full pay at the end of the day: "Even the immigration police agree that they’re real clans, mafia, the employers who hire labour like this. There are no proper contracts, I can tell you that for sure. The employers get away with lying to the labourers because they’re immigrants who don’t understand our laws. Some of them even tell the immigrants that they’ll help them to get their papers sorted out! But it’s all lies."

According to this union official, current Spanish law is ill-suited to combat these practices. There’s only a work inspection when a specific case is reported and backed up by witnesses. That’s hard to come by when you’re dealing with a clandestine community which is naturally inclined to avoid all contact with the authorities.