* FTSE 100 down 1.1 percent; four-session losing streak
* Banks weak as euro zone debt concerns weigh
* Miners down; bank lending to remain tight
By David Brett
LONDON, May 6 (Reuters) - Britain's leading shares fell for the fourth straight session on Thursday, led by banks and miners weighed by uncertainty over euro zone debt concerns, as Britain's electorate went to the polls.
The FTSE 100 <
> index closed down 80.94 points, or 1.5 percent, at 5,260.99 just above a support level of 5,259 given by analysts."Apprehension over the election, continuing debt contagion fears in the euro zone -- all the goodwill built up over the last few months after strong corporate results has been washed away with broader economic uncertainty," said Jimmy Yates, head of equities at CMC Markets.
The blue-chip index is down 5.3 percent for the week, on track for its worst weekly losses since early March 2009. It is down 2.8 percent for the year-to-date, after having been up almost 8 percent at the start of April.
Banks were the sharpest fallers on the FTSE 100, as European Central Bank President Jean-Claude Trichet did little to quell concerns over the debt crisis that are coursing through the euro zone. [
]Royal Bank of Scotland <RBS.L>, Barclays <BARC.L>, HSBC <HSBA.L>, Standard Chartered <STAN.L> and Lloyds Banking Group <LLOY.L> fell 3.7 to 6.5 percent.
British aerospace electronics group Cobham <COB.L> was the top FTSE 100 faller, down 5.6 percent after it said its defence business made a slow start to 2010 because of delays in the award of U.S. contracts. [
]Supermarkets group WM Morrison <MRW.L> lost 3.2 percent after posting a sharp drop in underlying quarterly sales growth. [
]Fellow food retailers J Sainsbury <SBRY.L> and Tesco <TSCO.L> shed 2.3 and 1.7 percent, respectively.
COMMODITY DRAG
Crude <CLc1> and metal prices fell across the board as the uncertainty over the euro zone hit demand fears and forced investors to the traditional safe haven of the greenback.
Miners Eurasian Natural Resources <ENRC.L>, Rio Tinto <RIO.L>, BHP Billiton <BLT.L>, Vedanta Resources <VED.L> and Anglo American <AAL.L> lost 0.7 to 3.9 percent.
Deutsche Bank said lending to the steel and iron ore industry is still tight, with the bulk of liquidity focused on the big firms, and availability is not seen easing until 2011.
The UK mining sector <.FTNMX1770> has lost more than 9 percent in the past week.
Integrated oils Royal Dutch Shell <RDSa.L> and BG Group <BG.L> fell 2.1 and 1.8 percent, respectively.
But peer BP <BP.L> gained 0.4 percent, extending Wednesday's recovery, following its sharp decline on fears over the cost of an oil spill in the Gulf of Mexico.
Oil explorer Cairn Energy <CNE.L> gained 1.2 percent, helped by an Exane BNP Paribas upgrade to "outperform", and peer Tullow <TLW.L> added 1.7 percent.
Rexam Plc <REX.L> added 2.8 percent after the world's largest maker of drinks cans said first-quarter results were ahead of its expectations. [
]Burberry <BRBY.L> gained 3.2 percent helped by an upgrade from Goldman Sachs and after upbeat first-quarter results from European luxury goods company Hermes. [
]Fund manager Schroders <SDR.L> was the top FTSE 100 riser, up 6.1 percent as it posted a sharp rise in first-quarter pretax profit. [
]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. [
]"You can see the FTSE going al lot lower tomorrow with a hung parliament and mixed U.S. non-farm payrolls," CMC's Yates said. (Editing by Karen Foster)