Hillary Clinton stumbles and FTSE 100 falls amid Trump victory 'uncertainties'
London's top-flight index slumped to a six week low as central bank jitters and concern over Hillary Clinton's health weighed on global markets.
The FTSE 100 Index closed 1.12% or 76.1 points lower at 6700.9 points - its lowest reading since August 3.
At one stage, the stock prices of all 100 companies listed on the FTSE 100 were trading in negative territory.
"With little on the economic agenda, a severe bout of panic has struck the global markets, causing the kind of declines not seen since the Brexit," Connor Campbell, a financial analyst at SpreadEx, said.
Meanwhile, a lower dollar drove sterling prices higher. The pound was up by around 0.35% at 1.332 against the US dollar, and higher by 0.29% at 1.186 against the euro.
Stocks across the globe slumped after Democratic presidential nominee Hillary Clinton was diagnosed with pneumonia just weeks ahead of the US election.
The alarm was raised after Mrs Clinton unexpectedly left a 9/11 ceremony in New York on Sunday, and was seen stumbling into her vehicle.
Jane Foley, a senior FX strategist at Rabobank, explained that the news was likely to worry investors "given the uncertainties about trade and foreign policy that a victory from Republican nominee (Donald) Trump would unleash".
Meanwhile, concerns have grown over the likelihood of an interest rate hike by the US Federal Reserve when committee members meet on September 21.
Across Europe, the German Dax closed 1.34% lower, while the French Cac 40 dropped 1.15%.
In oil markets, a falling dollar helped to support Brent crude oil prices, which rose 0.2 % to 48.11 US dollars per barrel.
UK stocks were also dragged down by Associated British Foods (ABF), which said that like-for-like sales at Primark are expected to fall by 2% over the year as warm pre-Christmas weather and a "very cold" March and April dampened its performance.
ABF added that post-Brexit currency movements would have both positive and negative effects on the group.
ABF shares closed lower by 10.8% or 341p, to 2815p.
Shares in retailer Marks & Spencer also took a dive, dropping 17.4p to 326.2p after announcing its high-flying executive Laura Wade-Gery will not return to work from maternity leave.
Ms Wade-Gery - who was once tipped to take the helm at M&S - was due to return to the company at the beginning of this month.
Banking shares including Lloyds, RBS and Standard Chartered were among the worst performers on the FTSE 100. Investec downgraded its outlook for RBS, saying the lender's recovery was "distant and uncertain".
Pharmaceutical companies AstraZeneca, Shire and Reckitt Benckiser made gains after Jefferies upgraded its view on AstraZeneca, which is developing a new drug meant to treat lung cancer.
The biggest risers on the FTSE 100 were Shire up 47p at 4750p, AstraZeneca up 39p at 4858p, Burberry up 9p to 1262p, and Carnival up 23p at 3372p.
The biggest fallers on the FTSE 100 were Associated British Foods down 341p, to 2815p, Marks and Spencer down 17.4p to 326.2p, Lloyds Banking Group down 2.34p to 56.97p, and RBS down 7.1p at 199.6p.