Online trading has added a new horror for dealers on the London Stock Exchange – ‘the snake in the grass.’ The problem is that after only a week of typing in orders on a computer, finely manicured city fingers are apt to hit the wrong key – sending an offer to sell shares in a different company at a bargain price. Some wily traders employ the ‘snake in the grass’ – and leave an buying order which anticipates such blunders so as soon as the cheap shares become available they are snapped up before the error can be corrected.