When Frankfurt social worker Stefan Mohr needed a new location for the troubled children he works with to express themselves through spray paint and graffiti, it did not take him long to find a potential site.
The trouble was, the vast area of fencing he found, down the road from the derelict warehouse the children had been using, was round the site on which the European Central Bank's new €1bn headquarters was being built.
Mohr contacted the bank. To his surprise, it not only agreed to let him use the fence around one of Europe's biggest building sites for graffiti, it offered €10,000 to pay for wooden panels to be attached to the fence, and for supplies of spray paint.
Mohr said he thought from the start that the homeless and underprivileged young people he works with would get a kick out of spraying on the site of such a politically symbolic building. But he had no idea that some of the world's most famous graffiti artists would help turn the fence into one of Frankfurt's biggest tourist attractions.
"All we wanted to do was find a place for kids to express themselves and show the public that graffiti is art, not vandalism," Mohr said.
"It has proved amazingly popular, with people coming from across the world to paint and take photos, and pictures from the wall are used in the press all over the world. We never thought it would get popular; all we wanted was somewhere to paint."
The graffiti, which is often highly political and includes caricatures of ECB president Mario Draghi and German chancellor Angela Merkel, has proved so popular that dozens of banks and money managers have been interested in buying the works.
"A lot of people want to buy pieces, but we didn't do this to make money," Mohr said. "We don't want to sell them. We like to see the pictures painted over. That's how graffiti works."
However, their landlord, the ECB, was allowed to buy one of the first works, showing two cocks fighting, and will display the piece inside the building when it opens in 2014.
Another artwork was sold after an investment fund owned by computer billionaire Michael Dell hired investigators to track down the artist behind a piece inspired by the Bond film Casino Royale. It shows Draghi and Merkel as 007 and a Bond girl inside a casino.
The painting, on plywood, now hangs in the Manhattan office of Dell's company, MSD Capital. Both MSD and Mohr declined to state how much the work was sold for, but it was less than the cost of shipping it to New York. The money went to the artist, rather than the publicly funded Under Art Construction project Mohr runs. Mohr has refused to sell any of the works since, despite more than 20 approaches.
Although many of the works depict Merkel, Draghi and the ECB in a derogatory way – in reaction to their role in forcing austerity measures on struggling eurozone economies – the bank does not censor the art.
"They don't tell us what to paint or not paint – just that there must be no fascism or sexism," Mohr said.
He added that about 60% of the works reflect the eurozone crisis, and that painters from Spain, Portugal and Greece are most likely to choose political themes. "Painters and young people have ideas that connect with the ECB and the problems of Europe."
Andrea Jürges, who looks after the project on behalf of the ECB, said the bank was happy to be satirised: "They can paint whatever they want – negative things about the ECB are fine in my view."
She said everyone at the ECB, Draghi included, is delighted that the project has proved so popular. "When they did a painting session one night recently, it was so packed you couldn't get near the front to see them."
The mayor of Frankfurt, Peter Feldmann, himself a former youth worker, supports the project and is calling on all construction sites in the city to allow graffiti on their perimeters. Jürges said: "I agree with the mayor: construction sites are ugly and this sort of thing is a wonderful opportunity to make something nice, and give young people space to express themselves."
The art works will continue to be replaced by new graffiti every three months until the new 45-storey building, designed by Austrian architect Wolf Prix, opens in late 2014. After that, anyone will be able to bid for pieces, with money going to the Under Art Construction programme.
guardian.co.uk © Guardian News and Media Limited 2010