By William James LONDON (Reuters) - British Prime Minister David Cameron is expected to win approval from parliament to join U.S.-led air strikes on Islamic State militants in Iraq at a specially convened session on Friday. A coalition including the United States and Middle Eastern allies such as Saudi Arabia and the United Arab Emirates has already started bombing Islamic State targets both in Iraq and Syria. France has also taken part in the strikes on the insurgents in Iraq, although so far **t in Syria. ...