London shares opened steady on Thursday, supported by gains in Imperial Tobacco after the cigaratte maker's third quarter figures.

The benchmark FTSE 100 index eased just 3.71 points or 0.06 percent to 6,583.72 points at 8:09 am.

Imperial Tobacco jumped 2.14 percent to 2,200 points as the company stood by its full year targets in the face of declining cigarette sales.

The number of 'sticks' sold dropped 4 percent in the nine months to September from a year earlier.

"Our full year expectations remain unchanged," chief executive Alison Cooper said.

"We continue to focus on maximising opportunities for our total tobacco portfolio in the EU against a backdrop of weak industry volumes and are driving good in-market performances in Asia-Pacific and Africa and Middle East, with our share improving in many markets."

Her strong statement also boosted shares in rival British American Tobacco, up 0.80 percent at 3,475.50 pence.

Other gainers included specialist distributor Bunzl, up 1.62 percent at 1,377 pence, and fund manager Old Mutual, up 1.46 percent at 200.90 pence.

AstraZeneca led the decliners, with the pharmaceutical giant shedding 1.43 percent to 3,202.50 pence. Miner Antofagasta eased 1.29 percent to 958.50 pence.