London's benchmark stock index finished the last half-day trading session of 2012 lower on Monday, completing the year nearly 6 percent higher than the end of last year.
The FTSE 100 ended down 27.56 points, or 0.47 percent, at 5,897.81 points on Monday.
Risk-sensitive stocks of banks, miners and energy firms weighed down the Monday half-day session.
Uncertainties over the U.S. "fiscal cliff" hang over the market, while some investors are confident that the U.S. will come to an agreement at the latest in early January.
Despite dull tradings in late December with the U.S. approaching the deadline, the London blue-chip index still added 0.5 percent in December, a seventh-consecutive month of gains as of June this year, the longest monthly gaining streak since February 2005.
The index, which closed at 5,572.28 points on December 31 of 2011, gained nearly 6 percent in 2012, buoyed mainly by gains in banking shares.
Yet it lagged behind its peers in Germany and France. The Frankfurt DAX index went up nearly 30 percent in the year, while the Paris CAC index rose 15 percent.
Peter Sullivan, head of HSBC European Equity Strategy, attributed gains in the European markets in 2012 mainly to economic growth outside Europe, especially in emerging markets, and decisive actions by central bankers.
"We expect European equities to rise in 2013. They key positives are that valuations are attractive and central banks are committed to Quantitative Easing (QE)," Sullivan told Xinhua