The decision to take up a prominent role for a new ALP group pressing for Palestinian statehood comes almost 40 years after Mr Carr launched Labor Friends of Israel with Bob Hawke, believing then that “Arabs were terrorists”. Mr Carr, premier of NSW for a decade before his stint as a federal minister, said Israel had changed.

His reversal of allegiance was prompted by his revulsion for an “apartheid” policy within Israel’s government as it fostered one set of racially based laws for the Jewish minority — and an inferior set for the Palestinian majority.

“It has become virtually impossible for the centre-left in politics to maintain support for the ‘ethno-nationalists’ who are now opposed to a Palestinian state and back expansion of Jewish settlements in occupied territories,” he said. “Social democrats find this impossible to live with.”

As Ms Gillard’s foreign minister in October 2012, Mr Carr led a cabinet and caucus revolt when the then Labor prime minister was determined to oppose a Palestinian bid for upgraded status in the UN. Eventually accepting she lacked a majority, Mr Gillard was forced into a humiliating backdown and Australia abstained from the UN vote.

Mr Carr wrote in his book Diary of a Foreign Minister, released in April, that Ms Gillard’s office had subcontracted out Middle Eastern policymaking to the wealthy and powerful Jewish lobby in Melbourne, which had infiltrated her government. In July he moved a motion from the floor of the NSW Labor conference, carried on ­voices with support from the ALP Left and Right, which committed the state party to a more pro-­Palestinian position. Mr Carr saidhis view was part of a worldwide trend that included conservatives and long-time supporters of Israel. He gave last month’s House of Commons vote endorsing recognition of Palestine, and recognition by Sweden, as examples.

Slotted into Ms Gillard’s ministry after Kevin Rudd quit to wrestle back the prime ministership, the former foreign minister said he was approached by rank-and-file party members to be patron of the fledgling Labor Friends of Palestine. He revealed his decision last night during an address to the Australian Friends of Palestine Association. Mr Carr said his “epiphany” on the changes in Israel occurred when he met a Christian volunteer who had gone to occupied territories to escort Palestinian children to school, and protect them from violence by ­Israeli settlers.

He still counted himself a friend of liberals in Israel, but it served the cause of a “just peace” to accept his new patron role.

Settlements had doubled in the past 54 months, settlers would not move and the Israeli government would not force them to leave.

Comparing Israel with pre-Mandela South Africa, Mr Carr said: “So an indefinite occupation morphs into the extremists’ goal of a Greater Israel. With one catch — it will have two classes of citizen. ‘A term used about another country on another continent,’ Ehud Barak told me when I, as foreign minister, discussed this very ­dilemma. The word is apartheid of course.”