Russia is preparing to plunge Europe into its worst conflict since World War II, British Prime Minister Boris Johnson has said, warning that any invasion of Ukraine would freeze Moscow out of global finance. “The fact is that all the signs are that the plan has already in some senses begun,” he said in a BBC interview broadcast on Sunday from the Munich Security Conference, after two Ukrainian soldiers were killed in attacks around rebel-held enclaves. Russian invasion plans would see its troops not just enter Ukraine from the rebel-held east, but from Belarus to the north and encircle the cap…