David Gillick fears there are more drug cheats in elite sport.
With revelations recently about cheating in professional tennis when Maria Sharapova admitted failing a drugs test, Russia have been given more time by the World Anti Doping Agency to prove their athletes are clean ahead of the Olympics.
The former Irish Olympian and European Champion was a guest on 'Now That's What I Call Sport' this morning.
He says things will get worse before they get better.
Listen to David's full interview with Jamie Moore, where he chats more about cheating, and how it feels to be competing in a race when you know some of those against you are cheating, by clicking play on the link below.
David Gillick was speaking an an ambassador for the VHI Women's Mini Marathon, which is on Bank Holiday Monday, 6th June 2016 at 2.00pm, starting on Baggot Street.
David will be combining his love of cookery with his athletics experience to provide plenty of healthy eating inspiration for the next 16 weeks. Every week David will be sharing his favourite recipes to fuel your training, including protein balls!
More info on www.vhiwomensminimarathon.ie
