"He finally broke and he walked them through what he had done. "They totted up his losses and by Sunday night they worked out that the losses were about £1.2 billion. The bank's bosses decided it had to cancel the bets immediately when the markets opened on Monday. "They started unwinding them on Monday morning - but because the market was failing the £1.2 billion loss became a £3.7 billion loss." Some senior City figures said the "positions" were so huge that dumping them on one day could have been enough to trigger Monday's stock market meltdown, the worst since...