FTSE 100 Index, British benchmark stock market gauge, decreased on Friday by 2.49 percent, or 161.07 points, to 6,300.63. The benchmark gauge fell 6.6 percent this week, marking the worst week since August 2011, data from Bloomberg showed.
Weaker-than-expected economic data from eurozone and a continued drop in oil prices have weighed on British stock markets.
Seasonally adjusted industrial output rose by only 0.1 percent in both the eurozone and the 28-nation European Union (EU) in October, the EU statistical office Eurostat said Friday.
Output in Britain's construction industry suffered a sharp fall in October, official figures showed.
In October 2014, output in the construction industry decreased by 2.2 percent compared with September 2014, said the Office for National Statistics (ONS).
Oil and gas sectors were also hit as crude prices continued their plunge. The decline was a major drag on the British stock index.
Brent Crude Oil Futures prices fell by 2.9 percent to 61.83 U.S. dollars per barrel on Friday, data from BBC showed.
United Utilities Group's share price increased by 3.56 percent, topped the gainers of the blue chips. Severn Trent, Sainsbury and Weir Group increased by 1.15 percent, 0.53 percent and 0.24 percent percent respectively.
Petrofac led the top losers of the blue chips with a share price drop of 6.35 percent, followed by Coca-Cola HBC AG (5.42 percent), Aviva (3.92 percent), St James's Place (3.79 percent) and Vodafone Group (3.43 percent).
The index has decreased 2.60 percent so far this year when adjusted in U.S. dollar.