For over 40 years, betting shops have enjoyed a near monopoly on high-street gambling, yet this could be about to change. A new breed of bookmakers, known as betting exchanges, is allowing punters to bet against the bookie' and each other. In response, the traditional shops claim these exchanges promote corruption, given that they permit customers to bet on a horse to lose, as well as win. Michael Robinson files a report for The Money Programme on a fight with billions of pounds at stake. Place your bets now.