The call came through late afternoon. The voice at the other end of the line - now the managing director of a famous fund-management institution, with tens of billions of pounds of pension fund money at his disposal - explained the bet. He was making a market in the number of finishers in the Grand National. He was offering 10-12. In other words, if I thought there would be fewer than 10 finishers, then I could "sell" at 10, and if there were only four finishers I would make six times my stake. I sold heavily at 10. The following day I watched the big race on the TV. There were 23 finishers. They seemed never to stop coming. The number, which remains a record to this day, is imprinted on my memory. I lost 13 times my money.