Stake factoring is a way of grading customers according to their success and is widespread in the betting industry

On any given Saturday, Rory would spend several hours glued to a screen flickering with hundreds of football and horse racing bets placed by customers of the Irish bookmaker Paddy Power.

One of multiple insiders from firms including Paddy Power Betfair, Ladbrokes and William Hill who spoke on condition of anonymity, Rory was part of an obscure corner of the gambling industry that exists to maximise profits by clamping down on successful punters.