He peaked at no. 7 in the world rankings in the mid-1980s, while also battling a serious gambling problem. Thorne began gambling when he frequented a billiard hall in central Leicester from the age of 16. In one incident, Thorne bet £38,000 on a match involving John Parrott, betting that Parrott would lose as he had lost his personal cue and had to use one supplied by the venue. Much to Thorne's dismay (not least because he was actually commentating on the match), Parrott recovered from a slow start to win, only worsening Thorne's debts. In an interview with "The Guardian" newspaper in 2004, Thorne admitted to placing bets of up to £20,000 on horses.