Britain's top shares fell on Thursday in choppy summer trading, as concerns over the global economic outlook heaped pressure on miners, while banks dropped as uncertainty over the euro zone debt situation undermined investor confidence, according to Reuters.
The UK benchmark index was down 122.63 points or 2.3 percent at 5,208.97 by 1052 GMT, having shed 0.5 percent on Wednesday, snapping a four-session winning streak in which the index jumped 7 percent.
Trading was also volatile ahead of the expiry of monthly futures and options on Friday.
Miners lopped the most points off the blue-chip index, retreating in tandem with the copper price on anxiety over a potential interest rate hike in top consumer China after a rise in its central bank's bill yields.
Heightening concerns over the demand picture, Morgan Stanley cut its forecast for global growth, citing "recent policy errors" in the United States and Europe, plus prospects of further fiscal tightening in 2012.
Economists at Deutsche Bank, meanwhile, downgraded their 2011 and 2012 growth forecasts for China.
In the mining sector, Xstrata led the market lower, shedding 5.5 percent.
Luxury group Burberry , whose sales are boosted by Chinese shoppers' love affair with luxury goods, also felt the heat, off 4.4 percent.
"Global growth concerns appear to be driving this and unfortunately I think we're going to be in this whip-saw pattern for a while until we get a bit of light at the end of the tunnel," Peter Dixon, economist at Commerzbank, said.
"This is probably a more typical summer day," Dixon said. "Volumes have dried up ... investors clearly don't want to commit themselves to taking big long positions in this kind of environment, so I suspect we're seeing some opportunistic selling having seen a reasonable rebound over the course of the past few sessions."
Financials extended their falls from Wednesday when a summit between the French President and German Chancellor failed to calm nerves about the euro zone debt crisis and left investors anxious about the impact of plans for a new tax on the industry.
Lloyds Banking Group and Barclays were the worst off, down 5 percent and 4.7 percent respectively.
Resolution bucked the weak sector trend, up 0.6 percent and one of only two FTSE 100 risers, as Citigroup repeated its "buy" rating on the life insurer in the wake of its first-half results earlier in the week.
Traders said volumes would likely remain subdued in the near term, with the latest corporate earnings season largely over.
There is however a batch of U.S. data set for release, with the main focus on July inflation numbers at 1230 GMT.
U.S. stock index futures pointed to a sharply lower open on Wall Street.