EU Commissioner Olli Rehn said UK should not ` ` threaten '' to leave the Union . Rehn : ` ` It is only to the mutual benefit of Britain and Europe that Britain stays as a member '' UK Prime Minister David Cameron has pledged to hold a referendum on membership . `` That 's the focus of 2013 . '' Rehn said threat of the breakup of the euro ` ` has all but disappeared ''
EU Commissioner Olli Rehn said UK should not ` ` threaten '' to leave the Union . Rehn : ` ` It is only to the mutual benefit of Britain and Europe that Britain stays as a member '' UK Prime Minister David Cameron has pledged to hold a referendum on membership . Rehn said threat of the breakup of the euro ` ` has all but disappeared ''