- Professor David Cowan is Britain's leading drugs scientist
- Oversaw London 2012 testing as director of UK's Drug Control Center
- Was denied full access to Sochi laboratory
- Discusses evolution of doping and anti-doping measures
(CNN)In the midst of an "unprecedented attack on the integrity of sport," this isn't an easy time for the men in white coats in their ongoing fight to beat the doping cheats.