The FTSE 100 gained 3.8% over the course of 2023, which was its best performance in three years but was far worse than all other major overseas markets.
London's blue-chip index finished up 10.50 points, or 0.1% on the day at 7,733.24, which is its best closing level since 23 May.
Meanwhile, the FTSE 250 index of mid-caps closed down 29.53 points on the day at 19,689.63, up 4.4% since closing out 2022, but below its high of just over 20,614 from February and all-time high of almost 24,200 in September 2021.
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Both of these were grossly underwhelming versus global stocks, with the MSCI World index surging more than 22% over the year.
The FTSE 100's rise was described as "paltry" by analysts in comparison to its international peers, with New York's S&P 500 having climbed 25% and the more tech-powered Nasdaq by over 45% during the year.
In Europe, the DAX in Frankfurt has jumped by over 19%, the CAC in Paris by almost 15%, Madrid's IBEX over 21% and Milan's FTSE MIB over 26%. Japan's and India's benchmarks rose 30% and 18%.
China was the biggest international disappointment, with the Shanghai Composite falling around 4.5%, while Hong Kong's Hang Seng slumped over 15%.
"The FTSE 100 has stumbled over the line, eking out a modest gain for the year but failing to shoot the lights out," said Susannah Streeter, head of money and markets, Hargreaves Lansdown.
The FTSE 100's performance was better than the 0.9% eked out in 2022, but below the stellar gains witnessed in 2021 of 14.3% - the best showing by the FTSE 100 since 2016.
Those bumper gains reversed similar losses in the year Covid came, 2020, (14.3%), which came on the back of a strong 2019, up 12.1%.
Before that, three further years of big movements in markets saw the FTSE 100 drop 12.5% in 2018, rise 7.6% in 2017 and soar 14.4% in 2016.