A Labor MP has defied Sir Keir Starmer with his pledge to back calls for a Gaza ceasefire in a crucial Commons vote.
Naz Shah, shadow minister for crime reduction, broke ranks with her party leader as she confirmed her plans to vote for an SNP amendment to the King's Speech supporting 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.
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.
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.
In a letter to MPs, the SNP's Mr Flynn wrote: “By refusing to join the United Nations to push for an immediate ceasefire, Westminster would be disregarding international law, condoning collective punishment and giving the green light light on the ongoing bombing of Gaza. has seen thousands of innocent children and civilians killed.
“People understand that the conflict in the Middle East is full of complexities. But within all this complexity, they also recognize a very human truth. People know that what we are all watching in Gaza is wrong and they want their MPs to do the right thing, show moral leadership and push for an immediate ceasefire.”
By tradition, frontbenchers are bound by a collective responsibility to support the party's position but, so far, Sir Keir has allowed some to deviate by voicing support for a Gaza ceasefire.
However, the Labor spokesman said the “room” for debate did not extend to a vote in Parliament because “this has an importance that everyone understands”.
The Commons showdown comes as Israeli forces entered Gaza's Shifa hospital.
The Israeli military had surrounded the facility as part of its ground offensive against Hamas, claiming the militant group was hiding military operations in the compound.
But with hundreds of patients and medical staff inside, the move risks civilian casualties.
Hamas raids on October 7 killed 1,200 people in Israel and saw more than 200 captured.
Reprisals, including a ground offensive in northern Gaza, by Tel Aviv forces have killed more than 11,000 Palestinians, according to the Hamas-run Gaza health ministry.
Foreign Secretary Andrew Mitchell is in Cairo on Wednesday for talks with his Egyptian counterparts and other partners on how to get more humanitarian aid to Gaza.