By mid-day, the FTSE had fallen 78.95 points, after a private survey showed that Chinese factories had contracted for the 14th consecutive month.
Mining stocks fell sharply thanks to the news, with Anglo American dropping 10 percent, Glencore down 6.5 percent and BHP Billiton down 4.8 percent. Meanwhile, Shares in HSBC fell by 1.4 percent after the bank reported that it had seen a 14 percent fall in first-quarter profits.
The bank noted that there had been extreme levels of volatility in the financial markets since the start of the year, although it emphasized that the fall in profits was not as bad as analysts had initially feared.
In the FTSE 250, the best performer of the day was Just Eat. Shares in the company climbed by 7.4 percent, up to 411.9p, after the company raised its profit forecast. Just Eat said that their full-year operating profit would be between £102 and £104 million, better than the previously expected £98m to £100million. The company said that it had increased the rate that it charges restaurants, and that this had allowed the corresponding increase in revenues.
Aberdeen Asset Management shed 9.6 percent after reporting a sharp decrease in its half-year profits. The fund management group says that it is continuing to be affected by a downturn in the economy of emerging markets.