The London markets slid as continued concerns over coronavirus case rises and the global economic recovery weighed on trading sentiment.
Travel operators and oil firms leaked losses once again amid concerns that there are major obstacles in the route out of pandemic restrictions.
Hawkish comments from two Bank of England members also drove concerns that bond-buying could be halted.
The FTSE 100 closed 79.17 points, or 1.12%, lower at 7,012.02 on Thursday.
Michael Hewson, chief market analyst at CMC Markets UK, said: “It’s been another negative day for European markets, as they continue to trade in the range they’ve broadly been in for the past few months.
“While the Dax and Stoxx600 have managed to put in marginal new record highs in recent days, there has been a distinct lack of follow-through, which appears to speak to uncertainty about a trifecta of factors; a continued increase in virus cases, the pace of recovery which appears to be slowing, and the transitory nature or otherwise of inflationary pressures.
“The energy sector is acting as the largest drag, with BP and Royal Dutch Shell lower on weaker oil prices, dragging the FTSE back towards the 7,000 level.”
The German and French markets were broadly in line with London, tumbling as a result of the broad slump in sentiment.
The German Dax decreased by 1.01% and the French Cac also moved 0.99% lower.
Across the Atlantic, the Dow Jones also dipped on the back of concern over its weak set of unemployment data for the past month.
Meanwhile, sterling lifted earlier in the session but lost steam as hawkish commentary in the US helped to bolster the dollar.
The pound was down 0.13% versus the US dollar at 1.384 and was 0.02% lower against the euro at 1.172.
In company news, tech giant Avast saw its shares soar after the FTSE 100 firm confirmed it is in talks with rival NortonLifeLock over a potential merger.
Norton said a possible combination with Avast “would bring together two companies with aligned visions, highly complementary business profiles and a joint commitment to innovation”.
Shares in Avast climbed by 91.4p to 595.6p as a result.
Just Eat Takeaway was the top index’s biggest faller despite reporting a spike in orders as takeovers helped bolster the firm’s bottom line.
Orders in the first six months of the year were up 61%, including a 51% jump in recently bought rival Grubhub.
Shares were 585p lower at 5,837p at the close of play.
B&Q owner Kingfisher has seen its shares rise after lifting its profit guidance in an out-of-hours Wednesday update.
It closed 3.7p higher at 366p after it said it is on track for 22% growth for the current half-year after a boost from the home improvement boom.
The prospect of extra supply being released to market as Opec+ members coalesce around a deal has weighed on oil.
Brent crude decreased by 0.43% to 74.44 dollars per barrel.
The biggest risers on the FTSE 100 were Avast, up 91.4p to 595.6p, Experian, up 73p at 3,050p, Prudential, up 22p at 1,366p, and Spirax-Sarco, up 185p at 14,440p.
The biggest fallers of the day were Just Eat Takeaway, down 585p at 5,837p, Next, down 388p at 7,402p, AstraZeneca, down 323p at 8,346p, and Taylor Wimpey, down 5.85p at 156.65p.