* Banks weak, HSBC down on negative broker comment
* Commodity stocks weigh; BG raises Pure Energy bid
* InterContinental Hotels up after results
* Jan UK inflation exceeds forecasts
By Jon Hopkins
LONDON, Feb 17 (Reuters) - Britain's leading share index fell 2.5 percent by midday on Tuesday, weighed by weakness in banks and commodity stocks, and expectations for early falls on Wall Street after data showed UK inflation was higher than forecast.
By 1156 GMT, the FTSE 100 index was 101.49 points lower at 4,033.26, having fallen 1.3 percent on Monday.
The Office for National Statistics said UK consumer prices fell 0.7 percent in January. That took the annual rate down to 3.0 percent from 3.1 percent in December, above forecasts for a rate of 2.7 percent and over the BoE's two percent target.
"With the threat of deflation a very real danger the MPC has a lot more work to do to keep inflation on target. It is still high-alert, all hands on deck time," said Rob Pike, head of trading at spread betting group ShortsandLongs.com.
Also on the data front, UK house prices fell 10.2 percent in December 2008 compared with a year earlier, the Department for Communities and Local Government said on Tuesday.
The banking sector was the biggest drag on UK blue chips at midday, pressured by a 5.3 percent fall from HSBC <HSBA.L> after some cautious broker comment.
Morgan Stanley, repeating its "underweight" stance on HSBC, said it was becoming more bearish on the outlook for profits.
Standard Chartered <STAN.L> also dropped, down 7.6 percent, while Lloyds Banking Group <LLOY.L> extended its recent slide, losing 6.2 percent, and Barclays <BARC.L> fell 0.9 percent.
Real estate group Land Securities <LAND.L> was the top FTSE 100 faller, down 9.3 percent after confirming on Monday that it was considering a rights issue.
Other property blue chips also fell, reflecting the gloomy economic picture, with Hammerson <HMSO.L>, Liberty International <LII.L>, and British Land <BLND.L> down 4 to 7.9 percent.
Heavyweight energy stocks were under pressure as crude prices remained below $37 a barrel, with BP <BP.L>, Royal Dutch Shell <RDSa.L>, and Cairn Energy <CNE.L> down between 0.8 and 3.1 percent.
BG Group <BG.L> shed 1.8 percent as the firm raised its bid for coal-seam gas explorer Pure Energy Resources by 25 percent to A$995 million ($646 million) on Tuesday, trumping a rival bid by Arrow Energy.
MINERS UNDER PRESSURE
Miners were weak as demand concerns continued, with Kazakhmys <KAZ.L>, Eurasian Natural Resources <ENRC.L>, Xstrata <XTA.L>, Anglo American <AAL.L> and Vedanta Resources< VED.L> all down between 3.5 to 6.2 percent.
Major investors in Rio Tinto <RIO.L> <RIO.AX> have poured scorn on efforts by the mining group to provide explanations of plans to raise $19.5 billion from state-owned Chinalco, shareholder sources said on Monday.
Advisers to BHP Billiton have surveyed investors in Rio Tinto about their support for an alternative to the Chinalco cash injection, the Financial Times said.
Rio Tinto <RIO.L> fell 1.7 percent and BHP Billiton <BLT.L> lost 4 percent.
But gold miner Randgold Resources <RRS.L> bucked the sector trend, up 1 percent as the price of the yellow metal <XAU=> rose to a seven-month high, buoyed by safe haven buying.
There were only a handful of other blue chip gainers, with InterContinental Hotels <IHG.L> standing out, up 1.3 percent after its full year results met forecasts despite strong headwinds in the sector.
U.S. blue chip futures <DJc1> pointed to a lower start on Wall Street on Tuesday, as the market reopens after a long holiday weekend, with investors bracing for quarterly results from retail behemoth Wal-Mart <WMT.N>. (Editing by Raji Menon)