The world's No. 2 bottler of Coca-Cola drinks (>> Coca Cola HBC AG), sank 5.3 percent after warning that volumes would fall for the rest of the year, citing a "sudden deterioration" in Russia, its biggest market.
More broadly, investors were on edge over the potential impact of sanctions announced by Russia in retaliation for penalties introduced by the West over events in Ukraine.
The FTSE 100 ended down 38.79 points, or 0.6 percent, at 6,597.37 points, its lowest close since April 16, meaning it has fallen more than 3 percent since a peak seen at the end of July.
Some traders, however, felt the index had found a floor for now.
"They're (investors are) still a bit nervous... but in the short term it's fairly well priced in," TJM Partners head of trading Manoj Ladwa said.
The Bank of England kept interest rates at their record low on Thursday, giving Britain's fast economic recovery more time to build even as differences among its policymakers become more apparent.
The European Central Bank also left interest rates unchanged.
Among insurers, RSA (>> RSA Insurance Group plc) shed 3 percent in a choppy day of trading after it outlined the details of its turnaround plan.
Berenberg analyst Sami Taipalus said in a research note that while RSA's balance sheet has been strengthened considerably, its economic capital ratio and targeted cost savings were lower than expected.
"Overall, we struggle to get overly positive about the contents of the release at this stage," Taipalus said.
Old Mutual (>> Old Mutual plc) was also down, falling 1.7 percent after foreign exchange trends dampened a headline jump in profit, traders said.
But fellow insurer Aviva (>> Aviva plc) rose 2.6 percent, one of the top FTSE 100 gainers, after unveiling a 4-percent rise in first-half operating profit as its European and UK general insurance businesses built on a strong start to the year.
ARM Holdings (>> ARM Holdings plc) also notched up good gains, rising 2.2 percent, as U.S. analysts added to some recent positive broker comment on the company, which sells blueprints for chip designs and receives royalties on every chip shipped by partners.
Benchmark, which reckons that royalty revenue will accelerate, lifted its rating on ARM to "buy" from "hold.
(Additional reporting by Alistair Smout; Editing by Louise Ireland)
By Tricia Wright