Britain\'s Chief Rabbi Jonathan Sacks said last night that British Jews are currently suffering the worst anti-Semitism England has known since the Holocaust. He said that anti-Semitism against the 280,000 Jews of England has increased significantly since the Sept. 11 attacks. Rabbi Sacks noted specifically physical and verbal assaults upon Jewish students and increasing synagogue vandalism. The anti-Semitic activities of the Islamic groups are taking place without sufficient supervision by the British society, he said, and called upon the country to \"take action\" before blood is shed. \"Someone has to sound an advance warning,\" said Rabbi Sacks.