Britain's top share index slipped to a one-month low on Wednesday as global equities suffered from nerves over the upcoming US presidential election and Standard Chartered was hit by broker downgrades.
Britain's blue chip FTSE 100 index, down for a third straight session, closed 1 percent weaker after slipping to its lowest level since late September. It declined along with European, Asian and US stock markets as polls showed the race for the White House was tightening.
Republican Donald Trump closed the gap on Democrat Hillary Clinton over the last week, according to some polls, spooking markets and prompting some to rethink bets of a Clinton victory.
"Anxious investors the world over are pricing in an even tighter US election race," said Mike van Dulken, analyst at Accendo Markets. "The probability of a Clinton win may remain high but a blindside Brexit result is also still very fresh in the memory of market participants."
The top individual faller was Standard Chartered, which dropped again after Tuesday's worse-than-expected results. It fell 4.3 percent on Wednesday after suffering broker downgrades from Deutsche Bank and Natixis, with total losses rising to nearly 10 percent in two sessions.
"Revenue stability is not enough ... The current share price implies even greater revenue growth," analysts at Deutsche Bank said in a note. "We think operating leverage for Standard Chartered remains challenging and see pressure on revenues in the coming years."
However, drugmakers outperformed the broader market, with analysts saying that a Trump win could lessen the risk of a more severe drug-pricing regime in the United States. GlaxoSmithKline and AstraZeneca were up around 0.3 percent.
Precious metals miner Fresnillo surged 3.6 percent, the top gainer in the FTSE 100 index, after prices of safe-haven gold rallied to a one-month high on uncertainty over the outcome of the US election.
British retailer Next rose 3.5 percent after it held its full-year profit forecast steady. With substantial domestic exposure, Next has been one of the worst performing FTSE 100 stocks this year, and slumped following Britain's vote to leave the European Union.
Peel Hunt raised its rating on the retailer to "buy" from "hold" after its results, saying like-for-like sales were negative but "not in freefall."
Mid-cap drugmaker Indivior surged more than 10 percent after raising its full-year revenue forecast as it sold more medicine to treat opioid addiction in the United States.