David Cameron has attacked Labour's position on Israel, saying Ed Miliband's party had "shown their true colours" during the Palestinian statehood vote in Parliament.
The Prime Minister said the Conservatives would always "stand behind the homeland of the Jewish people", and reiterated his opposition to boycotts and delegitimisation of Israel.
Mr Cameron launched a wide-ranging attack on Labour's approach to Israel and highlighted Mr Miliband's positioning over October's backbench debate on Palestinian statehood.
"For years, there has been cross-party consensus," he told supporters at Tuesday's Conservative Friends of Israel lunch in Westminster. "Yet here was the Labour leader, on a vote put down by a couple of backbenchers, a vote he could easily have avoided or walked away from, not just breaking that consensus, but actively whipping his own colleagues to support the motion.
"That is who you are now faced with leading Labour."
Mr Cameron said Labour local councils had promoted "abhorrent" boycotts of Israeli goods. He pledged to "defeat" delegitimisation of Israel.
A spokesperson for Mr Miliband later responded that Mr Cameron's remarks were "wrong, divisive and irresponsible. Ed and the Labour Party have zero tolerance of those who seek to delegitimise Israel and we continue to vigorously oppose boycotts."
In his 20-minute speech the Prime Minister also focused on the contribution of Jews to Britain. The community had for centuries been enacting the Big Society policy now promoted by his party, Mr Cameron said.
With a nod to the theme of Chief Rabbi Ephraim Mirvis's inauguration speech, Mr Cameron called on British Jews to "come with me" at next May's election. "Work with me, fight with me, for the values, the friendships and the country we all love," he said.
CFI director Stuart Polak told supporters that Mr Cameron's backing reminded him of the Ein Kamocha prayer - "there is none like you".
Andrew Heller, CFI chairman, had earlier told how dozens of Tory MPs who defended Israel's action in Gaza had been targeted by unprecedented levels of attack from anti-Israel activists.
Ilford North MP Lee Scott disclosed that leaflets had been handed out in his constituency this week claiming he was "an enemy of Islam". A source close to the MP said "all hell has broken loose". Last week the MP revealed that he had received five death threats in the past year because he is Jewish.
The lunch was attended by 700 people, including Home Secretary Theresa May, Chief Whip Michael Gove, Education Secretary Nicky Morgan and Culture Secretary Sajid Javid.