A recovery in mining stocks helped the FTSE 100 Index to start Wednesday in positive territory, although it later declined.
Big miners were on the up as the price of copper stabilised. BHP Billiton (LON:BLT) gained 10p to 1066p, Anglo American (LON:AAL) lifted 4.7p to 689.1p and Rio Tinto (LON:RIO) increased 15p to 2286p.
Plant hire group Ashtead (LON:AHT) revved up 41.5p to 958.5p as the owner of A-Plant boosted first quarter profit by 23% thanks to strong demand in July.
The FTSE 100 Index initially shrugged off continuing jitters over China's economy, rising as high as 6110, before falling back to stand 9.89 points off at 6048.
British construction industry figures showed a slight rise in business activity and jobs in the sector in August.
The headline seasonally adjusted Markit/CIPS UK Construction Purchasing Managers’ Index registered 57.3 in the month, up from 57.1 in July, with any reading above 50 indicating growth.
Traders were hoping for a lift from the data after Tuesday's downbeat manufacturing figures.
Stateside, the focus will be on the US ADP employment index. Consensus is for an increase in ADP employment growth of 200,000 in August, up from 185,000 in July.
Oil majors fell as the price of a barrel of Brent crude declined 1.7% to US$48.75. A barrel of US light crude receded 2.2% to US$44.4. BP (LON:BP.) backtracked 2.95p to 346.45 and Royal Dutch Shell (LON:RDSB) was 19.5p off at 1626.5p.
Car parts and bike retailer Halfords (LON:HFD) reversed 40.1p to 469.9p after it forecast worse-than-expected second quarter cycling sales, although it said trading in other areas was robust.
Among smaller stocks, Empyrean Energy (LON:EME) drifted 0.38p to 5.88p as it revealed steady production despite major flooding.
Miner Mwana Africa (LON:MWA) fell 0.02p to 1.12p on news of plans to raise just short of £3.7mln to shore up its balance sheet and expand its diamond operation.