* Commodity stocks top-weighted losers
* Barclays leads banking sector lower
* UK in recession after fastest GDP fall since 1980
LONDON, Jan 23 (Reuters) - Britain's leading share index fell 1.6 percent by midday on Friday, on course for its fifth day of losses as commodity stocks and financials weighed and after confirmation that the UK economy had entered recession.
By 1114 GMT, the FTSE 100 <
> was down 63.93 points at 3,988.30, below the 4,000 mark for the first time since early December last year. The UK benchmark is down nearly 10 percent this month after plunging more than 31 percent last year -- its worst annual drop since its launch in 1984.Britain went into recession at the end of last year for the first time since 1991, as the economy shrank at its fastest pace in nearly 30 years.
"It's not the fact that we are in recession but it's the degree which we are in recession that has taken the market further downward," said Keith Bowman, an equity analyst at Hargreaves Lansdown.
"It's still a major question mark hanging over banks in the UK, the U.S. and almost on a global basis on some degree."
Barclays <BARC.L> slid 12.7 percent, on course for its ninth-straight session of losses, on concerns it may require further capital or be nationalised by the government.
Chief Executive John Varley said the bank would prefer to pay the UK government in cash rather than shares if it takes part in a scheme to insure risky assets.
Standard Chartered <STAN.L>, Royal Bank of Scotland <RBS.L>, HSBC <HSBA.L> and Lloyds Banking Group <LLOY.L> lost 0.8 to 4.9 percent.
A group of lawmakers said the British government must reveal to taxpayers the full cost of its support for banks during the financial crisis.
UBS cut its year-end target for the FTSE 100 to 4,900 from 5,800 and lowered its forecasts for dividend growth to 7 percent for 2009 from 14 percent. "Sterling weakness is helping to support UK dividends, but the risks remain biased to the downside," the broker said in a note.
Sterling <GBPJPY=R> hit a record low against the yen as losses in the pound mounted after the GDP data.
SLIPPERY OILS, DULL METALS
Oil producers took the most points off the index as crude prices <CLc1> eased. BP <BP.L>, Royal Dutch Shell <RDSb.L>, BG Group <BG.L> and Tullow Oil <TLW.L> were down between 1.1 and 2.1 percent.
Miners also languished, with Anglo American <AAL.L>, BHP Billiton <BLT.L>, Rio Tinto <RIO.L>, Kazakhmys <KAZ.L>, Xstrata <XTA.L> and Vedanta Resources <VED.L> off 2.9 to 4.3 percent.
Insurers fell on investor jitters ahead of fourth-quarter earnings from major U.S. counterparts next week, with vague talk of financial difficulties in the sector in Germany further weighing on sentiment.
Aviva <AV.L>, Legal & General <LGEN.L>, Old Mutual <OML.L> and Prudential <PRU.L> dropped 6.4 to 10.9 percent.
AstraZeneca <AZN.L> added 1.1 percent. The Wall Street Journal said Pfizer <PFE.N>, the world's largest drugmaker by revenue, is in talks to acquire rival Wyeth <WYE.N> in a deal that could be valued at more than $60 billion. (Editing by Simon Jessop)