Almost six years since the first allegations of “mechanical doping” in cycling, on Saturday a hidden booster motor was finally found in a bicycle being used at a major event, when an inspector at the world cyclo-cross championships in Zolder, Belgium, located a small motor in the bottom bracket of a machine reportedly belonging to the pre-race favourite in the women’s under-23 event, the European champion Femke van den Driessche of Belgium.

The gold medal went to the British cyclist Evie Richards, who has the honour of being the first-ever champion in the category. The GB academy rider, who took a silver medal in last year’s junior world mountain bike cross-country title, escaped on the opening lap and remained clear until the death, but her success was overshadowed by the scandal that broke afterwards.

The Union Cycliste Internationale said in a statement “that pursuant to the UCI’s Regulations on technological fraud a bike has been detained for further investigation following checks at the Women’s Under 23 race of the 2016 UCI Cyclo-cross World Championships. This does not concern any of the riders on the podium. Further details will be shared in due course.”

The Belgian media outlet Sporza reported that the Belgian Cycling Federation had confirmed that the detained bike belonged to Van den Driessche. Ironically, Van den Driessche had abandoned the race due to a mechanical issue shortly before the bike was scrutinised. Van den Driessche’s name did not feature in the official results on the UCI website on Saturday evening.

However, the rider’s father told the newspaper Het Nieuwsblad [see footnote] that the bike was not his daughter’s. “It’s not Femke’s bike,” he reportedly said. “Someone from her team, who sometimes trains with her, brought the bike to the pit. But it was never the intention that she would ride it … Femke has absolutely not used that bike in the race. We are strongly affected by what’s happened. Femke is totally upside-down” .

The UCI’s head of off-road racing, Peter van den Abeele, said that the governing body had been testing a new detection system, not because it had any particular indication that fraud was going on, but because this seemed a good opportunity. The offence is officially termed “technological fraud” and carries a minimum six-month suspension and a fine of between 20,000 and 200,000 Swiss francs.

Rumours of “mechanical doping” first surfaced in 2010, when the Classic and time-trial specialist Fabian Cancellara was forced to defend himself against apparently unfounded allegations that he had mechanical help. At the time, a consultant to the governing body said that he estimated that the use of a small electric motor hidden in the bottom bracket could save between 60 and 100 watts as the rider pedalled, a considerable boost to performance.

Not long afterwards the UCI began examining machines on a random basis, using a scanner and later a small camera. There have been high-profile searches for the boosters but nothing has ever been found, as was the case last year at the Tour de France, for example, when half a dozen machines including that of Chris Froome, were examined after the finish of stage 18 through the Alps.

• This footnote was added on 2 February 2016. The translation of comments by Femke van den Driessche’s father was taken from a VeloNews report.