The FTSE 100 index initially added more than 30 points but was later 17.59 points down at 6550.74 - adding to a fall of more than 150 points over the last few days.
The top flight has fallen by 2.5 per cent, or 167.8 points, since last Friday’s close.
Tony Cross, market analyst at Trustnet Direct, said London’s equity market had rounded out the week in a somewhat lacklustre tone. “Traders have struggled to find any real momentum off the back of the day’s data.”
Sentiment about the global economic picture was improved by a second day of China’s currency stabilising after sharp declines earlier in the week.
Elsewhere, legislators in Greece approved a bail-out package for the debt-laden country after an acrimonious all-night debate on the terms of the rescue deal which include sharp spending cuts and tax hikes.
But in the wider eurozone, official figures showed growth in the 19-nation bloc slipped to 0.3 per cent for the April-June period, down from 0.4 per cent in the first quarter.
Meanwhile, the US crude contract price for oil fell to a six and a half year low during the session amid concerns over a slowing economy in China and a glut of oil supply on the market.
BP shares fell 1 per cent, or 3.9p, to 379.3p, while Royal Dutch Shell dipped 19.5p to 1814p.
The biggest risers on the FTSE 100 were TUI up 48p at 1,162p, Hikma Pharmaceuticals up 59p at 2,400p, St. James’s Place up 18p at 980p and Barratt Developments up 11.5p at 653p.
The biggest fallers on the FTSE 100 were Glencore down 4p at 172.9p, Smiths Group down 22p at 1,179p, Weir Group down 24p at 1,462p and Shire down 80p at 5,200p.