Producers of precious metals were particularly hard hit. Analysts blamed falling prices for gold and silver and adverse currency movements.
Fresnillo, which owns the world's biggest silver mine, was down 4.5% and Randgold was down 4.2%.
"Gold is in no man's land," said Alastair McCaig, market analyst at IG Index.
He says that investors are concerned that gold could fall below $1,200 dollars an ounce, which would make some gold mines unviable.
Gold is currently trading at $1,266 dollars an ounce.
In China iron ore prices fell to the lowest level in almost five years, which hit shares in other miners.
Rio Tinto fell 0.73% and BHP Billiton was down 0.37%.
BP was 2.59% higher. Shares had slumped 6% on Thursday after a US judge found the firm "grossly negligent" over the 2010 oil spill.
The ruling has made investors cautious over the firm.
"I'm not buying BP here. The ruling opens up the door in the United States to more fines for BP," said Beaufort Securities sales trader Basil Petrides.
"The US government has got its knife out for BP and it's sharpening the blade," he said.
On the currency markets the euro was trading 0.13% higher, but still below the $1.30 level.
It fell below the $1.30 level on Thursday in reaction to a surprise cut in interest rates by the European Central Bank.
The Bank also launched a programme to buy private sector debt, in another effort to boost European economies.
The pound was down 0.10% against the dollar at $1.6314.
(Close): The FTSE 100 index of leading blue-chip shares closed the day down by 0.36% at 6853.40.