The top shares index moved higher on Thursday influenced by a big batch of blue chip results, with energy issues the top gainers after strong results from BG Group, but disappointments from miner Rio Tinto and Vodafone weighing.

At 8:51 a.m., the FTSE 100 <.FTSE> index was up 25.51 points, or 0.4 percent at 5,901.44, having closed 0.2 percent lower on Wednesday.

BG GroupL> was the top FTSE gainer, up 1.1 percent after the gas producer said it expected to grow production at 7 percent per year to 2020, as it posted fourth-quarter earnings of $1.48 billion (933.34 million pounds) against consensus of $1.11 billion.

Other energy issues <.FTMNX0530> were also in demand, the top performing blue chip sector, as crude ticked higher.

Drugmakers moved higher too, with Shire adding 0.8 percent ahead of its fourth-quarter results due later in the day.

Banks <.FTMNX8350> provided support as a sector as euro zone debt concerns eased and investors took the view that Greece was seen edging nearer to getting its debt crisis under control.

Greece's leaders were continuing talks to resolve one remaining issue to wrap up a deal on a bailout package crucial to avoiding a messy default. Greek officials said pension cuts were the sticking point.

Investors were awaiting the Bank of England February rate decision, due at 12 p.m. , with the Bank expected to leave its key interest rate unchanged at the record-low of 0.5 percent.

The Bank is also seen announcing 50 billion pounds in additional quantitative easing asset purchases, though the decision of the nine-member Monetary Policy Committee may not be unanimous given recent more upbeat economic news.

Britain faces slumping back into recession if Q1 of 2012 produces negative GDP growth, in which case more QE could be too little too late. If previous QE has not stopped the UK going into a double dip, why would a fraction more change the economy's direction, said Simon Furlong, a trader at Spreadex.

The European Central Bank will also announce its latest rate decision at 12:45 p.m., with no change expected either.

MINER MISHAP

Miners were the main drag on blue chip sentiment, led by Rio Tinto which shed 1.0 percent after its full-year results disappointed.

Rio reported a 6 percent drop in underlying second-half profits and took a $9.3 billion charge mainly against its aluminium business, although it appeased investors somewhat with a huge 34 percent dividend hike, underscoring its long-term confidence.

Market heavyweight Vodafone also weighed on the downside after posting third-quarter results slightly below forecasts as increasingly tough trading in Spain and Italy overshadowed solid performances in emerging markets and northern Europe at the world's largest mobile operator.

Vodafone Q3 results make sobering reading. Not because they're much of a surprise ... More because one has to pause to reflect on the fact that revenues, profits and FCF are all moving in the wrong direction , Liberum Capital said in a note.

Hargreaves Lansdown was the top FTSE 100 faller, down 3.6 percent, after the investment manager posted a 13 percent drop in net new business during its first half year to December 31 as economic gloom and falling stock markets hit investor sentiment.

And among other blue chip fallers after results and trading updates on Wednesday, aero enginemaker Rolls-Royce dropped 1.6 percent, Diageo , the world's biggest spirits group, lost 0.5 percent, British Land fell 2.4 percent, and Tate & Lyle shed 1.1 percent.

(Reporting by Jon Hopkins; Editing by Helen Massy-Beresford)