By Jan Wolfe ALEXANDRIA, Va. (Reuters) – A former British national accused of engaging in “brutal hostage-taking” as an alleged member of an Islamic State cell nicknamed “the Beatles” appeared in a U.S. federal court on Wednesday for the start of his criminal trial. El Shafee Elsheikh, 33, is standing trial in federal court in Alexandria, Virginia, just outside Washington, on charges including lethal hostage-taking and conspiracy to commit murder. U.S. authorities have said Elsheikh was one of four ISIS militants belonging to the cell, which operated in Iraq and Syria, and whose member were ni…