The FTSE 100 ended a resurgent November on a bum note as it slid into the red following a slump in confidence throughout the session.
Banking stocks and oil majors made some of the biggest falls as traders also sought to cash in on gains.
London’s top flight closed 101.39 points lower at 6,266.19 at the end of trading on Monday.
David Madden, market analyst at CMC Markets, said: “Equity markets are largely showing small losses as we approach the end of the final trading session of the month.
“November has been a great month for stocks thanks to a number of big pharma countries that have made great progress in terms of developing potential vaccines for Covid-19.
“It would appear that today’s broadly bearish move in stocks has been driven by profit taking from recent gains and to a lesser extent, concerns about the health crisis itself.”
Sentiment was far more mixed elsewhere in Europe, with the German Dax in a far more robust position.
The German Dax was 0.33% down while the French Cac moved 1.42% lower.
Across the Atlantic, the Dow Jones opened around 1% down as traders took a step back after the benchmark hit an all-time high last week, with bullish sentiment fading away.
Meanwhile, sterling made gains as it benefited from the dollar’s continued rough spell, as the US greenback dropped to a level last seen in April 2018.
The pound rose by 0.05% versus the US dollar at 1.333 and was 0.17% up against the euro at 1.116.
Oil giants BP and Shell were both notably poor performers on Monday with eyes on an Opec meeting and hopes that current production cuts will be extended.
The resultant caution among oil traders pressed down on prices, as other commodity stocks also slumped.
The price of a barrel of Brent crude oil decreased by 1.31% to 47.64 US dollars.
In company news, Lloyds Banking Group dropped in value after it appointed the head of HSBC’s high street banking division as its next chief executive.
Charlie Nunn will replace Antonio Horta-Osorio, who is stepping down in the summer, and will be expected to get to grips with the potential for negative interest rates – an idea flagged by the Bank of England.
Shares in Lloyds declined by 1.67p to 35.62p at the close of play.
Elsewhere, outsourcing giant G4S dipped after a suitor trying to snap up the firm extended the deadline for shareholders to agree to the deal.
GardaWorld Security, a Canadian-based rival, said investors can now have up to December 16 to decide if they want to accept its 190p-a-share offer. Shares closed 7.1p lower at 221p.
Pub chain JD Wetherspoon slid into the red after its founder and chairman, Tim Martin, accused the Government of making “reckless decisions” in its Covid-19 policies.
Trading sentiment was also particularly hit by the decision by Welsh leaders to ban the sale of alcohol and limit pub opening times to 6pm in the run up to Christmas. The pub chain saw shares drop 44p to 1,104p.
The biggest risers on the FTSE 100 were JD Sports, up 43p at 776.2p, Spirax-Sarco, up 285p at 11,135p, Experian, up 61p at 2,646p, and London Stock Exchange, up 186p at 8,106p.
The biggest fallers on the FTSE 100 were Phoenix, down 69.4p at 716.8p, Compass, down 94p at 1,324p, BP, down 15p at 247.65p, and Royal Dutch Shell B, down 69.8p at 1,234.2p.