ANOTHER dose of Greenspan worries, plus the crushing defeat of the Conservatives in the Wirral South by-election, played on investors' nerves yesterday, briefly driving the FTSE 100 index below the 4,300 mark.

And markets across Europe were not being helped by a sudden amid-morning burst of speculation that Germany might be contemplating a two-year delay of European monetary union.

The main depressant for London came from Wall Street's Thursday performance, where a late sell-off drove the Dow Jones Industrial Average down 58 points. US Treasury bonds endured an uncomfortable session, too, retreating a quarter of a point.

Wall Street's unhappiness was evident again in early trading yesterday when the Dow fell over 50 points, before staging a rally which brought the average back to almost level not long after London closed.

That performance surprised many market observers, coming in the wake of a downward revision in fourth-quarter gross domestic product. The annualised figure was lowered from 4.7 per cent to 3.9 per cent. The Chicago purchasing managers' index came in stronger than expected, but not dramatically so.

At the end of a session marked by flurries of selling, Footsie had comfortably regained the 4,300 level, eventually finishing 30.9 off at 4,308.3.