The integrity of greyhound racing has been called into question by a Panorama investigation which has exposed blatant cheating and the drugging of dogs at the heart of the sport. The undercover investigation caught a trainer revealing how he dopes greyhounds in order to effect betting coups - some of which he claims to have paid out up to £150,000. The programme's findings have prompted animal welfare campaigners to call for the government to reconsider the sport's self-regulatory status.