Anxiety as London's top shares have fallen nearly 2.4%,

London's top shares have fallen nearly 2.4%, while other European markets have seen even bigger falls, amid anxiety about the health of the global economy.

By lunchtime, the FTSE 100 index was down 135.32 points to 5,536.98.

At the same time, share indexes in Frankfurt and Paris were down 2.7% and 3.8% respectively.

Analysts said US Federal Reserve boss Janet Yellen's gloomy economic assessment on Wednesday had added to investors' worries.

In testimony to Congress, Ms Yellen said financial conditions in the US had become "less supportive" of growth and warned of the "increased volatility" in global financial markets.

Official Figures Shows UK Economy Grew by 0.5% in fourth quarter

The Office for National Statistics show an improvement on the third quarter figure of 0.4%.

But the 2.2% annual growth in 2015 was down compared with 2.9% in 2014.

Output in the three months to December was 1.9% higher than a year earlier, down from 2.1% in the third quarter and the smallest increase since early 2013.

Despite the annual pace of growth being the slowest for three years, it still means the UK economy is one of the fastest growing developed nations.