The company says it can provide welders, tilers, painters and bricklayers: "The Slovaks are independent professionals and pay all their taxes and health insurance costs in Slovakia. This means you won't have any problems with taxes or social contributions and a big saving for you!"

The company claims that the Slovakians are up to 50% cheaper than Belgian workers.

The company is based in Slovakia. Its Dutch manager told Het Nieuwsblad: "Everything is legal. It's not unfair competition. It's all within the rules. That's the way the EU is run."

The Slovakian workers hand the Dutch company part of the 19 euros that they charge per hour. The company's manager insists that by Slovakian standards what remains is quite generous.

Belgium's Building Confederation is incensed by the news. Robert de Mûelenaere: "This is a company based abroad offering services in Belgium but that hasn't been recognised as a temping agency. These people are bogus self-employed. It's illegal. Action must be taken against it."

Gerrit Van de Mosselaer of the Social Security Ministry: "We are routinely confronted with such practices. Building workers are allowed to come to Belgium to work for a while, but they have to have worked in Slovakia beforehand. Otherwise they have to pay their taxes here."

The Social Security Ministry is contacting other EU states too in a bid to exchange information and tackle the problem more quickly.