Punch-drunk Belgium is reeling from a new shock after a senior police officer confirmed last week what has long been rumoured: that some of the country’s leaders indulge in sex parties, known ironically as “ballets roses”.

Amusing and appalling in turn, the testimony of Georges Marnette, a senior Brussels policemen, might appear to make a welcome change from the horrors of recent months. But this is not mere entertainment: the stories may provide an important insight into the mores of a ruling class that has outraged ordinary people.

At times, Belgium has been in the throes of a near-revolution, with hundreds of thousands on the streets demanding an end to the political patronage that, they believed, had helped – by omission if not commission – a paedophile ring to murder children and escape arrest. It has not been a time of many laughs for anyone.

All the same, it was with a mixture of knowing winks and barely suppressed laughter that a parliamentary commission investigating another of the country’s most mysterious scandals heard the evidence of M Marnette. Belgian newspapers usually refer to the portly M Marnette as “un superflic”, and mean it. In fact, his evidence was more reminiscent of Inspector Clouseau.

“Yes, we used to go the bars, the gay and lesbian clubs and the sex parties,” he said, his bushy moustaches bristling at the memory of his past achievements. Infiltrating such establishments was no easy matter; it was not a job to be done wearing “jeans and a leather jacket”.

As for M Marnette, he was clearly a master of disguise. “I wasn’t going to hang round wearing my holster while everyone else was either naked or in dressing-gowns. But if I was in a dressing gown, that didn’t mean that I was doing any sexual acrobatics myself.”

The vision of leading politicians, judges and policemen indulging in orgies may tickle the Belgian taste for the absurd. But the light relief provided by tales of lax morals in high places is wearing off. For the “ballet rose” is also the perfect metaphor for the corruption, freemasonry and the vulnerability to blackmail of the country’s political élite.

The public will be learning more about the “ballets roses”, and the identities of dignitaries who attended them, from the evidence of other policemen who “infiltrated” this exotic demi-monde. It is a world of outwardly respectable private clubs in discreet suburbs of Brussels, Antwerp and Liège, but where, on arrival, members remove not just their coats, but their tops, bottoms and underwear as well.

For the moment, it looks increasingly unlikely that the two inquiries obsessing Belgians will yield new insights into how those in power exploit their positions, let alone name the guilty men or bring improvements. But M Marnette’s testimony, and his naming in camera of two senior establishment figures who performed at the “ballets roses”, caused a minor sensation.

Georges Marnette

Many had dismissed the “ballets roses” as Belgium’s Loch Ness monster – much talked about, rarely seen and its existence never proved. But now it emerges that they were not the only exotic entertainment enjoyed by the ruling classes.

The “ballet rose” itself implies the presence of young, but not necessarily under-age, girls. To cater for other tastes, there are also “ballets bleus” (young men), “partouzes” (run-of-the-mill orgies) and even “ballets de confiture” (apparently extreme Right-wingers like to strip and smear themselves with jam).

The parliamentary inquiry truly gripping the nation is the one examining the case of Marc Dutroux, who has confessed to murdering four young girls, and the way it was handled by the authorities.

The second inquiry has caused less of a furore, but the crimes it is reviewing, dating back 10 years, were even bloodier and more traumatic than the paedophile murders. These were the spectacular series of hold-ups, known as the Brabant killings, that terrorised Belgium in the early 1980s and claimed the lives of 28 people. They remain unsolved.

The usual explanation is that the killings were an attempt by the far Right, in league with the security services, to destabilise the country. But the suspicion has long persisted that some of the victims were not gunned down at random, but targeted because of their links to “ballets roses”.

Hugo Coveliers, a Belgian senator, argues that the “ballets roses” are not independent of one another, but part of a system “which operates to this day and is used to blackmail the highly placed people who take part”.

To many who hoped that rage at last year’s paedophile scandal could be channelled into political reform, the “ballets roses” are at best a digression, at worst an attempt by the authorities to throw the two inquiries off the scent of the real villains. The very existence of the two commissions of inquiry has signalled a desire for change. The public may take further encouragement from the fact that, for the first time since the armed robberies began in 1982, police last month released identikit photos of possible suspects.