Britain's top shares shed 0.8 percent early on Thursday, as energy stocks fell after Royal Dutch Shell's quarterly results disappointed and investors were cautious ahead of the latest Bank of England monetary policy decision.
By 0917 GMT, the FTSE 100 index was 39.22 points lower at 5,213.93, after the index snapped a three-session winning streak on Wednesday, shedding 0.6 percent.
The blue-chip index had previously gained 2.7 percent since ending near to a three-month low last Thursday.
Royal Dutch Shell dropped 2.3 percent on Thursday after it posted a 75 percent fall in fourth-quarter profit to $1.18 billion, as it was punished for its strong positions in the ailing natural gas and refining businesses.
BG Group, which is due to report its fourth-quarter numbers on Friday, shed 0.4 percent.
Banks continued to lose ground, following recent strong gains, ahead of the Bank of England's monetary policy announcement.
Heavyweight HSBC shed 1.7 percent, Standard Chartered lost 1.3 percent, while Royal Bank of Scotland, Barclays and Lloyds Banking Group were 1.1 to 2.8 percent lower.
"The financials are a little bit of a worry looking at some of the banking indices certainly state-side, and chart wise they look as if they are in a downward trend that will weigh on the market going forward," said David Morrison, market strategist at GFT Global.
The Bank of England announcement is due at midday, although the central bank is not expected to raise interest rates from the current record low level until October at the earliest, according to a Reuters poll of over 60 analysts.
The majority of economists polled expected the central bank to leave its bond purchase programme at the most recent cap of 200 billion pounds ($325 billion), pausing its quantitative easing policy.
The European Central Bank will also issue its latest pronouncement on monetary policy at 1245 GMT, with no changes also expected.
Miners extended the previous session's losses as metal prices were knocked again as the dollar strengthened after U.S. data on Wednesday.
Antofagasta, Lonmin, Rio Tinto, Xstrata and BHP Billiton were off 2.7 to 4.4 percent.
"Copper has had a dreadful few days which is an indication as to how investors are viewing the recovery going forward", Morrison added.
Unilever fell 2.1 percent after the consumer goods giant beat fourth-quarter sales growth forecasts but its West European region stayed weak and the group needed to cut prices more than expected to get its overall sales growth.
VODAFONE DELIGHTS
Vodafone prevented the index from posting even sharper losses.
The world's largest mobile phone operator by revenue soared 4.8 percent, hitting a one-month high and topping the FTSE 100 gainers' list, after posting third-quarter revenue ahead of forecasts and raising its outlook.
Aviva, Britain's second-biggest insurer, rose 0.6 percent after it said its life sales rose 21 percent in the final quarter of 2009, and added that it was well-placed to benefit from an economic upturn in its major markets.
Some defensive issues were in demand as investors' risk appetite waned. British American Tobacco and Imperial Tobacco gained 0.2 and 0.1 percent respectively.
Drugmaker GlaxoSmithKline rose 0.5 percent ahead of its fourth-quarter results due at 1200 GMT.
In the United States, the latest weekly jobless claims numbers due for release at 1330 GMT will be viewed as a precursor of Friday's U.S January jobs report.
