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LONDON, June 12 (Reuters) - Britain's FTSE 100 index is seen opening 20 to 26 points lower, or as much as 0.4 percent, on Friday, according to financial bookmakers. For more on the factors affecting European stocks, please click on
* Futures for the index were down 0.4 percent at 0623 GMT.
* The UK blue chip index closed up 0.2 percent at 6,846.74 points in the previous session.
* RIO TINTO - The miner said it was assessing an about $300 million non-cash impairment charge related to its shareholding in Energy Resources of Australia Ltd.
* British telecoms regulator Ofcom proposed controls on the wholesale prices BT charges for products using leased telecoms lines, which provide vital high-speed links for businesses and providers of superfast broadband and mobile services.
* BWIN.PARTY - The company said independent trustees of both Emerald Bay Limited and Stinson Ridge have chosen to place up to 50 million shares in Bwin.Party.
* TED BAKER - The company said there was a 24.2 percent increase in group revenue for the 18-week period from Feb. 1 to June 6.
* PETRA DIAMONDS - Petra said it expected revenue for the year to be approximately $430 million.
* GLENCORE - A month-long lockout at the fourth-largest aluminum smelter in the United States ended on Thursday after unionized workers voted to ratify a new five-year labor deal with Century Aluminum, the union said on its website. The United Steelworkers Local 9423 and Century, controlled by Swiss commodities trade house Glencore, resumed negotiations last week over a labor deal at the 244,000 tonne-per-year Hawesville, Kentucky, smelter.
* ROYAL DUTCH SHELL - A divided federal appeals court on Thursday rejected an effort by a coalition of environmental groups to revoke federal approval of Royal Dutch Shell Plc's oil spill response plans related to drilling on Alaska's remote Arctic coast.
* The German government is holding "concrete consultations" on what to do in the case of a bankruptcy of the Greek state, German newspaper Bild said, citing several people familiar with the matter.
* The International Monetary Fund dramatically raised the stakes in Greece's stalled debt talks on Thursday, announcing that its delegation had left negotiations in Brussels and flown home because of major differences with Athens.
* Oil futures dipped after Saudi Arabia said it was ready to raise output further to meet strong demand.
* London copper edged up from near three-month lows hit the session before, but was facing its fourth consecutive weekly fall as worsening economic indicators from top consumer China undermined its demand outlook.
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> Other business headlines Multimedia versions of Reuters Top News are now available for: * 3000 Xtra : visit topnews.session.rservices.com * BridgeStation: view story .134 For more information on Top News visit topnews.reuters.com (Reporting by Atul Prakash)