The reason given by the court of appeal for throwing out the case was fully accepted by the Cassation Court: The main evidence had been obtained illegally. In addition, magistrates and investigators had conspired to make it appear that the documents were obtained legally.

Those documents contained the names and details of 8,000 account holders of KB-Lux, a Luxembourg-based subsidiary of Kredietbank, now part of KBC. The files contained details of 300 cases in which the bank had set up special arrangements to help wealthy clients escape paying tax.

But the documents had been stolen by disgruntled employees of KB-Lux, who first tried to use them as blackmail. They were brought to investigators by an informant who was on a police blacklist indicating he was not to be used.

Investigators proceeded to set up an elaborate cover that would allow the files to be “found” accidentally. When the truth came out, the case was thrown out. Fourteen people, including three customers, six executives of KB-Lux (including CEO Damien Wigny) and five executives of Kredietbank (including CEO Remi Vermeiren) now walk free after a case that has lasted 16 years.

The only person left likely to suffer any consequences from the case – said to be the largest in Belgian fraud history – is the investigating magistrate, now one of the most senior magistrates in the country. Jean-Claude Leys was manipulative and failed in his duty of impartiality, the courts have said. He covered up the falsification of official records, pressurised witnesses and colluded with police in inventing a cover story for the files.