By Costas Pitas LONDON (Reuters) - The British government is "terrified" of intervening militarily in Iraq ahead of elections due next year and is happy to posture rather than take real action, an ex-senior general who previously helped lead NATO missions said on Tuesday. Islamic State insurgents - radical Islamists who want to re-create a mediaeval-style caliphate straddling Iraq and Syria - have swept across **rthern Iraq in recent weeks, pushing back Kurdish regional forces despite coming under U.S. air strikes. ...