The top share index edged higher in choppy early trade on Wednesday, as investors cheered updates from Intertek and Meggit, while worries over Europe's debt crisis prevented the index from pushing higher.

London's blue chip index <.FTSE> was up 12.90 points or 0.2 percent at 5,530.34 by 0858 GMT, having erased intraday losses on Tuesday, after decent U.S. retail sales figures boosted confidence that the world's biggest economy was in better shape than had been thought.

Investors continued to reward companies taking steps to increase their earnings in austere conditions.

Testing firm Intertek rose 3.1 percent as it reported an 8 percent underlying revenue rise and said it expected the diversity of its business to help it continue to achieve single-digit growth.

Aircraft parts supplier Meggitt , which was downgraded by Citigroup recently on valuation grounds and hosts an investors seminar on Wednesday, bounced 2.1 percent as it announced contract wins in Australia and the UK.

Consumer goods group Reckitt Benckiser (RB) , which warned of slowing growth late last month, gained 1.9 percent as Citigroup issued a bullish note on the stock.

RB remains one of our top picks across the European consumer staples space, Citigroup said, adding it expected the group to generate growth ahead of its global peer group.

Trading across the FTSE remained extremely choppy, with the FTSE volatility index, a gauge of investor nervousness, up 8.8 percent in November.

EUROPE CONCERNS

Investors nerves continued to jangle as the political and economic outlook in the euro zone remained uncertain.

Italian Prime Minister designate Mario Monti was expected to unveil Italy's new government, while in Athens, new prime minister Lucas Papademos expects an easy win in a confidence vote, but investors said they wanted more action on the economic front from the new leaders.

Although the new Italian leader stated yesterday that he is confident that Italy can overcome the recent crisis, many investors are still waiting to see real action on the ground rather than rhetoric, and are therefore continuing to punish Italy as a result, Zahid Mahmood, senior dealer at Capital Spreads.

Italian 10-year bond yields remained near 7 percent, a level of funding costs seen as unsustainable in the long run for the debt-ridden country, while Spanish 10-year bond yields were up at around 6.1 percent.

Highlighting the impact the debt crisis is having on corporates, ICAP , down 5.6 percent, posted a dip in first-half earnings and said its voice-broking business had been hit by banks looking to cut costs in the wake of market turmoil caused by the euro zone debt crisis.

Anglo-Dutch publishing and events group Reed Elsevier shed 0.3 percent after its third-quarter update, which Peel Hunt described as worthy, if slightly dull.

Small-cap video games retailer Game Group slumped more than 30 percent after issuing a profit warning.

Ex-dividend factors also took a hefty 15.28 points off the FTSE 100, mostly accounted for by market heavyweight Vodafone which traded without the attractions of a special dividend as well its half-year payout.

BSkyB , Marks & Spencer , J Sainsbury and Vedanta Resources also traded ex-dividend.

On the macroeconomic front, unemployment numbers will be released at 9:30 a.m., with the October claimant count seen rising by 20,000, after a 17,500 increase in September. September's ILO unemployment rate was seen increasing to 8.2 percent from 8.1 percent.

November's Bank of England inflation report will be published at 10:30 a.m.

(Additional reporting by Jon Hopkins; Editing by David Holmes.)