Rogue blunderer

NOT all the fancy systems in the world, it seems, can put an end to simple, human cock-ups. On May 14th London's stock exchange went for more of a tumble than it would otherwise have done because a trader at a bank keyed in the wrong number of shares on his trading screen. The mistake meant that a sell order on a basket of shares worth a reported £30m ($43m) turned into one valued ten times that. The FTSE 100 index, already slightly down, fell by 2.2% in the final moments of trading, when the trade was made.