Three Labor MPs have defied Sir Keir Starmer to back calls for a ceasefire ahead of a crucial Commons vote.
Shadow ministers Naz Shah, Helen Hayes and Afzal Khan broke ranks with their party leader as they signaled plans to vote on an SNP amendment to the King's Speech backing the ceasefire.
Labor members face the sack if they back the amendment as Sir Keir tries to avoid a damaging split in his parliamentary party.
Labor MPs were told to abstain from the SNP's move and were instead told to back Sir Keir's position calling for longer “humanitarian pauses” instead of a ceasefire.
SNP Westminster leader Stephen Flynn said parliament must “show moral leadership” and vote to support an immediate cessation of hostilities.
Labor members who rebel in support of a rival amendment will normally face dismissal for cracking the party whip.
A shadow crime reduction minister, Ms Shah said a “humanitarian disaster” was unfolding in Gaza as she backed calls for an “immediate ceasefire”.
He told the Commons: “I will support the amendment seeking an immediate ceasefire.”
The Bradford West MP also invoked Robin Cook, who resigned from Sir Tony Blair's cabinet over the 2003 invasion of Iraq.
“Make no mistake, this is a humanitarian disaster and that is why I urge members to support an immediate ceasefire on all sides and push for the release of the hostages,” he said.
Ms Hayes, shadow minister for children and early years, said her “conscience” told the room she should support a ceasefire
Both the Labor and SNP amendments have been selected for a vote on Wednesday night by Commons Speaker Sir Lindsay Hoyle.
A party spokesman said earlier: “This is a whip vote and every MP knows what that means.”
The party's position on the Middle East conflict has led to internal divisions, with the leadership backing the UK government's position of pushing for humanitarian pauses in the fighting to allow aid to Palestinians trapped in the bombed-out territories, but it doesn't ask for a full stop. of hostilities.
However, several shadow ministers have openly called for a ceasefire and dozens of councilors have quit the Labor Party over their refusal to support a permanent end to the violence.