* FTSE 100 up 0.4 percent after four-session losing streak
* Miners rally helped by steadier metal prices
* Banks stay weak as euro zone debt concerns weigh
By Jon Hopkins
LONDON, May 6 (Reuters) - Britain's leading share index held firm at midday on Thursday, having recovered from an opening drop, with a rally by miners and insurers offsetting further falls by banks on fears that the Greek debt crisis could spread.
By 1047 GMT, the FTSE 100 <
> index was up 20.06 points, or 0.4 percent at 5,361.99, having rallied from an opening fall to a session low of 5,267.50. That was just above a support level of 5,259 highlighted by a Charles Stanley technical analyst on Wednesday.The blue-chip index dropped 69.18 points, or 1.3 percent on Wednesday, taking the four-session decline to almost 5 percent.
"Considering the dramatic falls the FTSE 100 has suffered, we have been due a bit of a relief rally but in truth there is not much in today's moves so far that suggest that the woes we have seen over the last week are over for now," said Joshua Raymond, market strategist at City Index.
Miners provided the main prop for the blue-chips, rallying following recent sharp falls after Australia imposed a tax on the sector, helped by steadier metal prices. The mining sector <.FTNMX1770> has lost over 9 percent in the past week.
Xstrata <XTA.L>, Kazakhmys <KAZ.L>, Rio Tinto <RIO.L>, BHP Billiton <BLT.L>, Vedanta Resources <VED.L>, Anglo American <AAL.L> and Fresnillo <FRES.L> gained 0.7 to 4.2 percent.
Insurers also saw good demand. RSA Insurance <RSA.L> took on 3.1 percent after it said in a trading update that net written premiums rose 5 percent in the first quarter and confirmed key growth and profitability targets for 2010. [
]Peer Prudential <PRU.L> rallied 3.7 percent after falls on Wednesday following a delay to the rights issue linked to the insurer's purchase of AIG's <AIG.N> Asian operations.
Among other financials, fund manager Schroders <SDR.L> was the top FTSE 100 riser, up 5.1 percent as it posted a sharp rise in first-quarter pretax profit. [
]Well-received results also supported beverage can maker Rexam <REX.L>, up 3.3 percent. [
]Supermarkets group WM Morrison <MRW.L> lost 1.6 percent as it posted a sharp drop in underlying quarterly sales growth. [
]Fellow food retailers J Sainsbury <SBRY.L> and Tesco <TSCO.L> shed 0.4 and 0.3 percent, respectively.
BANKS A DRAG
Banks were the main drag on sentiment as euro zone debt crisis concerns continued to take a toll. Royal Bank of Scotland <RBS.L>, Barclays <BARC.L>, HSBC <HSBA.L>, and Standard Chartered <STAN.L> lost 0.8 to 1.6 percent.
But Lloyds Banking Group <LLOY.L> advanced 0.2 percent.
Integrated oils were weaker as crude <CLc1> held around $80 a barrel, with Royal Dutch Shell <RDSa.L> and BG Group <BG.L> falling 1.1 and 0.4 percent, respectively
But peer BP <BP.L> gained 1.2 percent, extending Wednesday's recovery following sharp recent falls on fears over the costs of an oil spill in the Gulf of Mexico.
Oil explorer Cairn Energy <CNE.L> gained 4.1 percent, helped by an Exane BNP Paribas upgrade to "outperform".
Voting was underway in the British general election, with overnight opinion polls showing the Conservative lead firming, leaving it a close call as to whether they will win an overall parliamentary majority. [
]The Bank of England has moved its normal monthly rate announcement to Monday to avoid clashing with the election.
The European Central Bank holds its monthly meeting later on Thursday and, while it is expected to keep rates unchanged at 1 percent, it is likely to try to assure markets that it can prevent the Greek debt crisis from spreading.
(Editing by Erica Billingham)