BP last night delayed a critical test to determine if a new cap on its blown-out Macondo well can arrest the flow of oil that has gushed into the Gulf of Mexico for the past 12 weeks.

"We decided that the process may benefit from additional analysis that will be performed [yesterday and today]," said retired Coast Guard Admiral Thad Allen, overseeing the U.S. response to the spill.

Regardless of the results, BP should be able to contain the flow with oil-siphoning vessels by mid-July, he sai...