The Swiss investigation has been going on for two years, since a list of the names of account holders was unearthed. According to the Antwerp authorities, 170 named individuals are concerned, most of them in the diamond sector, and including some senior names. The figure, according to the financial daily De Tijd, which disclosed the investigation, represents one in four of the traders in Antwerp. “This drags the credibility of the industry right down,” the paper said.

A spokesperson for the diamond industry said the sector would do all it could to cooperate with the investigation. “Our desire is for the 185 companies to do business in an honest and proper manner. All we can do it to give as much support as possible to the bodies that exercise control over the business.”

Meanwhile Carl Devlies, secretary of state for anti-fraud measures, rejected calls for a special fraud policy for the diamond sector. “We’re talking about 25% of the industry, which means that three-quarters are working well, I would say,” Devlies said. “We need to create a framework in which fraud can be tackled, but we can’t work out a specific policy for each individual sector.