The FTSE is on track to hit its lowest closing level in almost a year amid fresh warnings the eurozone crisis will engulf Italy and Spain.
Update (3pm): The Dow Jones dropped 35 points in early US trading on Wednesday after better-than-forcast employment figures had momentarily lifted investor sentiment.
A deal by US lawmakers to raise the country's debt ceiling passed its first hurdle last night but failed to lift shares after dreadful manufacturing data.
US markets have reversed earlier gains after manufacturing data raised further doubts about the strength of the economic recovery.
With the US on the verge of pushing through a deal to raise the country's debt ceiling by at least $2.1trn, American comedian Remy Munasifi gives his own unique take on the proposal.
Global markets climbed overnight and in early trading on Monday on news the US has agreed an outline solution to its debt crisis.
Dow Jones Indexes has launched a shipping index, which which measures the performance of 25 leading dividend-paying companies in the shipping industry.
The FTSE has plunged in mid-afternoon trading with banking stocks hard hit after Santander released poor results and the impasse over the US debt ceiling shows no sign of ending.
The Dow Jones closed more than 90 points lower on Tuesday amid escalating fears the US will default on its debt for the first time in its history.
UPDATE 9am: Global stockmarkets have almost doubled losses seen in early trading on growing concerns the debt crisis in the eurozone may spread to Italy and Spain.