The biggest percentage fall was seen in the South African insurer and financial services group Old Mutual, which dropped 4 3/4p, or 5.2%, to 85 1/4p, just a smidgen above the year's low. The shares have been weak of late, partly because of the troubled South African rand. Buyers in London chased them up to 90p yesterday while the Johannesburg market was closed for the day. When it reopened today, one of the first things South African investors did was sell the stock.