The London market opened 1.9% lower in the first minute of trading, extending losses from Friday over a report showing no growth in US employment during August.
Investors are worried about the prospects for global growth.
Before the open this morning, Senior Trader at ETX Capital Manoj Ladwa said: "Equities look set for another leg lower this morning as the market factors in the impact of zero job creation in the US for August.
"Banks could bear the brunt of the selling as pressure mounts from US regulators over the selling of toxic mortgage debt.
"Commodity stocks are also expected sharply lower as both copper and crude oil for December delivery trade lower in early trading."
The FTSE lost 2.3% on Friday in the wake of the official data on US jobs which highlighted precious little activity in the crucial private sector.
In Asia overnight, there were similar falls in both the Nikkei and Hang Seng - giving their first reaction to the disappointing performance in the world's biggest economy.
In Europe today, both the German DAX and CAC 40 were down almost 3%. Source