Reuters: There is little hope that near-term efforts by London-based BP Plc to choke off a leaking underwater oil well will succeed, experts said on Friday, raising the prospect of an environmental disaster on the scale of the 1989 Exxon Valdez oil spill. BP, the majority owner of an undersea well leaking 5,000 barrels (210,000 gallons or 955,000 liters) a day of oil into the Gulf of Mexico, is hoping two relatively quick fixes bear fruit before a pair of relief wells that could take up to …