* Miners weak; Deutsche Bank downgrades BHP Billiton
* Banks gain; Barclays up on hopes no new funds needed
* Vodafone weak as Banc of America-Merrill Lynch cuts target
By Jon Hopkins
LONDON, March 27 (Reuters) - Britain's top share index was 0.3 percent lower at midday on Friday, having reversed earlier gains, with weakness in miners countering gains from the oil majors and banks.
By 1205 GMT, the FTSE 100 index <
> was 12.34 points lower at 3,912.86, having closed 24.95 points, or 0.6 percent, higher in the previous session."We're in a period of contemplation at the moment ... No one is expecting too much radical from the G20 meeting next week but if there could be some sort of co-ordinated agreement, a linking of arms that would have to be seen as a result," Richard Hunter, strategist at Hargreaves Lansdowne, said.
"You have to allow time for the measures already taken to take traction, so in the absence of any obvious catalyst the market is likely to just tread water," Hunter added.
Heavyweight mining issues were lower at midday as metal prices eased back and broker comment had an impact.
Deutsche Bank cut its earnings estimates and targets for the sector as it sees no underlying recovery yet in the sector. It downgraded its stance on BHP Billiton <BLT.L> and Kazakhmys <KAZ.L>, down 2.3 percent and 4.8 percent respectively.
Lonmin <LMI.L> was the biggest FTSE 100 faller, down 5.7 percent, while Eurasian Natural Resources <ENRC.L>, and Fresnilo <FRES.L> lost 5.8 percent and 4.2 percent respectively.
Rio Tinto <RIO.L> bucked the weak sector trend, adding 1.5 percent. Australia may force Rio Tinto <RIO.L> to "Australianise" its top management as a condition for approving its $19.5 billion tie-up with Chinese state-owned metals firm Chinalco, a report said on Friday. [
]Mobile phones heavyweight Vodafone <VOD.L> was a drag on blue chip sentiment, off 2 percent as Banc of America-Merrill Lynch cut its target to 160 pence to reflect lower growth.
Insurers were also weak, reflecting some uncertainty over European Union plans to reform the sector to make it safer for policyholders. [
].Aviva <AV.L>, Prudential <PRU.L>, Friends Provident <FP.L>, and Admiral Group <ADM.L> shed between 1.3 percent and 3.7 percent.
BANKS IN DEMAND
Banks were the strongest gainers on the FTSE 100 index, extending a recent recovery, with Barclays <BARC.L>, Lloyds Banking Group <LLOY.L>, Royal Bank of Scotland <RBS.L> and HSBC <HSBA.L> up between 0.4 percent and 8.7 percent.
Barclays has gained more than 200 percent since hitting its low so far this year, on Jan. 21.
Britain's financial regulator has concluded a stress test on Barclays and is satisfied the bank does not need any fresh capital, a person familiar with the matter said on Friday. [
]The British government will have a big part in the country's banking sector for years to come but competition and choice for consumers must be maintained, UK Finance Minister Alistair Darling said on Friday. [
]Blue chip defence stocks found support, with BAE Systems <BAES.L> up 3.1 percent and Rolls-Royce <RR.L> ahead 1.9 percent, snapping a recent weak run.
Britain's economy slowed even more sharply than expected in the last three months of 2008 as construction output plunged, official data showed on Friday.
The Office for National Statistics said the economy shrank by 1.6 percent in the fourth quarter, the sharpest decline since 1980. Analysts had expected an unchanged reading of -1.5 percent.
The annual rate of decline was revised down to 2.0 percent, the sharpest fall since 1991. [
]House prices in England and Wales fell 16.5 percent on the year in February, the Land Registry said on Friday. [
]Investors will eye a rash of U.S. data later, with personal income, personal consumption, PCE price index and the Reuters/University of Michigan sentiment index.
Ahead of the data, U.S. stock index futures pointed to a lower open on Wall Street after strong gains on Thursday. (Editing by Andrew Macdonald)