Standard & Poor's said in its Global Economic Outlook on Thursday that it has halved its forecast for Italy's GDP growth this year to 0.4% from 0.8%. It said the Italian economy was set to be among the hardest hit by the repercussions of the Iran war.    It also cut its forecast for British growth by 0.4 of a percentage point form 1.4% to 1.0%.  It said the Eurozone's GDP will increase by 1% this year, having previously forecast growth of 1.2%. [...]