Further share gains from blue chip giant Vodafone failed to keep the FTSE 100 Index in positive territory today as falling oil prices put energy stocks under pressure.
The Government's defeat over Britain's involvement in any US-led military action against Syria caused Brent crude to fall below 115 US dollars a barrel, down from highs of 117 dollars a barrel earlier this week as the crisis took hold.
Despite ongoing e xcitement over Vodafone's imminent multi-billion pound exit from the United States, t he FTSE 100 lost much of yesterday's gains, down 26.4 points to 6456.7.
An upward revision of second-quarter GDP in the United States helped markets on Thursday, despite fuelling expectations that it may prompt the Federal Reserve to begin tapering asset purchases next month.
There was further caution amid more US economic data on consumer confidence, spending and manufacturing, with futures trading pointing to a flat opening on Wall Street.
Shares in Vodafone maintained their froth following yesterday's confirmation t hat it had resumed discussions over the potential sale of a 45% stake in Verizon Wireless.
Speculation over the potential deal, which analysts believe could be worth up to 130 billion US dollars (£84 billion), caused an 8% rise in its share price yesterday, leaving the mobile phone giant at its highest point since 2002.
Shares lifted another 2% or 3.6p to 208.4p amid hopes a deal will be announced next week.
But lower crude prices hit oil majors BP and Royal Dutch Shell, down 4.7p to 446.3p and 23.4p to 2178.8p respectively.
Exploration firm BG Group also shed 15.3p to 1229.8p, while Petrofac was 28p lower at 1395p.
Further signs that Britain may be on the brink of a housing boom helped housebuilders move higher.
Nationwide said house prices rose 0.6% in August, up 3.5% year-on-year, while Bank of England data revealed mortgage approvals for home purchases leapt to their highest level for more than five years in July.
Charles Church owner Persimmon added 13p to 1115p in the top tier, while Bovis Homes gained 10.5p to 757.5p in the FTSE 250.
In other corporate news, Frankie & Benny's owner The Restaurant Group was 2% or 9p higher at 548p after reporting a 15% rise in half-year profits to £30 million.
The performance was in line with City forecasts, although the company said sales growth slowed in July amid the heatwave.