European and US shares have fallen sharply as poor US retail sales figures and Citigroup's first quarterly loss added to fears of a US recession.
London saw its biggest one day fall since August
In London the FTSE 100 index of leading shares slumped by more than 3% - its biggest one-day fall since the height of the credit crunch in August.
And on Wall Street the Dow Jones and Nasdaq lost 2.3% and 2.5% respectively.
Sales in US shops fell by 0.4% in December from a year earlier, as consumers tightened their belts.
And Citigroup, the giant US banking firm, reported a $9.83bn (£5bn) net loss for the last three months of 2007, taking its total writedowns as a result of exposure to sub-prime loans to $18bn.
"The losses at Citigroup - whilst fully expected - still seem to be unsettling traders across the Atlantic, whilst at the same time the lacklustre US retail sales figures are confirming that the economy is slowing," said CMC Markets trader Jimmy Yates.
The FTSE 100 ended 190.1 points lower at 6,025.6 - wiping more than $45bn off the value of London's leading companies.
It has lost 7% since the beginning of the year as the US economic situation continues to unravel.
Meanwhile the Paris index ended 2.83% down at 5,250.82, while Frankfurt's Dax closed 2.1% lower at 7,566.4.
And on Wall Street, the gloomy data hit key markets with the Dow Jones index falling 277 points, 2.2%, to close at 12,501.11. The Nasdaq index fell 2.5% percent to end at 2,417.59.