LONDON (Reuters) - British foreign minister Boris Johnson said on Friday it was  appalling  that Russia had blocked a U.S.-drafted resolution to renew an international inquiry into who is to blame for chemical weapons attacks in Syria.  It is appalling that the UN Joint Investigative Mechanism has been closed down,  Johnson said in a statement.  The United Kingdom will not let the end of the Joint Investigative Mechanism stop work with international partners to identify and hold accountable those responsible for using chemical weapons.  The vote at the United Nations on Thursday sparked a war of words between Russia and the United States in the Security Council. 