Reigning Tour de France champion Chris Froome says he has previously raised concerns about the existence of 'motorised doping' to cycling's governing body.
The issue is in the news after the Union Cycliste International confirmed the discovery of evidence pointing to a bike containing a motor at the UCI Cyclo-cross World Championships.
In comments to cyclingnews.com, Froome said he had told the UCI to remain vigilant on the issue.
"For the last few years now there have been rumours about motors being concealed within the bikes. It's a concern that I've had, something that I've brought up with the UCI independent commission when I sat down with them and said 'listen, from my point of view there are these rumours, it would be my advice that the UCI implements controls and measures to start checking bikes more regularly,'" he said.