David Carruthers was sitting in a London restaurant overlooking the Thames, a clear view of the City financial district beckoning. He was hungry, impatient for service, troubled by a persistent cough, but otherwise in typically feisty, talkative mood.

The smartly attired 49-year-old BetonSports chief executive was keen to expand on the British company he had taken to market two years ago and the online gambling industry at large. He was clearly relishing the opportunities for growing the company further. Barely a week later, this Edinburgh-bred food fanatic, lover of fine wines and expert snooker player appeared in a Dallas court dressed in a prison-regulation orange jump suit, his hands and legs shackled to a chain-gang of other inmates.