Isaac Herzog (L) and Tzipi Livni, leaders of the centre-left Zionist Union party, speak on the phone with potential voters at their party's headquarters in Tel Aviv March 15, 2015. Israel's centre-left opposition is poised for an upset victory in next week's parliamentary election, with the last opinion polls before Tuesday's vote giving it a solid lead over Prime Minister Benjamin Netanyahu's party. REUTERS/Nir Elias (ISRAEL - Tags: POLITICS ELECTIONS)