Three Labour frontbenchers have defied Sir Keir Starmer to back calls for a ceasefire ahead of a crunch Commons vote.
Shadow ministers Naz Shah, Helen Hayes and Afzal Khan broke ranks with their party leader as they signalled plans to vote for an SNP amendment to the King’s Speech backing a ceasefire.
Labour frontbenchers are facing the sack if they back the amendment, as Sir Keir bids to avoid a damaging split in his parliamentary party.
Labour MPs have been ordered to abstain on the SNP move and have instead been told to back Sir Keir’s position calling for longer “humanitarian pauses” rather than a ceasefire.
SNP Westminster leader Stephen Flynn has said Parliament must “show moral leadership” and vote in favour of backing an immediate cessation of hostilities.
Labour frontbenchers who rebel to back a rival amendment would normally face the sack for breaking the party whip.
A shadow minister for crime reduction, Ms Shah said a “humanitarian catastrophe” is taking place in Gaza as she backed calls for an “immediate ceasefire”.
She told the Commons: “I will be supporting the amendment which seeks an immediate ceasefire.”
The Bradford West MP also invoked Robin Cook, who resigned from Sir Tony Blair’s Cabinet over the invasion of Iraq in 2003.
“Make no mistake, this is a humanitarian catastrophe which is why I urge members to back an immediate ceasefire on all sides and push for the release of hostages,” she said.
Ms Hayes, a shadow minister for children and early years, said her “conscience” told her she should back a ceasefire.
“We must all of us be able to stand in front of our own constituents with integrity and at peace with our own conscience on the issues that matter most to them.
“My conscience tells me that I must call for a ceasefire today,” the Dulwich and West Norwood MP said.
Shadow business minister Afzal Khan, who represents Manchester Gorton, said: “If we had a ceasefire yesterday 144 Gazan children would still be alive today. Israel has already crossed every red line imaginable and broken international humanitarian laws.
“History has shown us that military action alone does not resolve conflicts and Israel’s use of force will not resolve this one.
“We need to call an immediate ceasefire now. My constituents have demanded this and I will not refuse them. Supporting a ceasefire is the very least we can do.”
Both Labour’s amendment and the SNP’s one have been selected for a vote on Wednesday evening by Commons Speaker Sir Lindsay Hoyle.
A party spokesman earlier said: “This is a whipped vote and every MP knows what the consequence of that means.”
The party position on the Middle East conflict has led to internal splits, with the leadership backing the UK Government’s position of pushing for humanitarian pauses in the fighting to allow aid to reach Palestinians trapped in the bombarded territory but stopping short of calling for a total cessation of hostilities.
However, several shadow ministers have openly called for a ceasefire and dozens of councillors have resigned from Labour over its refusal to back a permanent halt to the violence.
In a letter to MPs, the SNP’s Mr Flynn wrote: “By refusing to join the United Nations in pressing for an immediate ceasefire, Westminster would be disregarding international law, condoning collective punishment and giving the green light to the continued bombardment of Gaza, which has seen thousands of innocent children and civilians killed.
“People understand that the conflict in the Middle East is full of complexity. But amidst all that complexity, they also recognise 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 press for an immediate ceasefire.”
By tradition, those occupying frontbench positions are bound by a collective responsibility that they support the party’s position but, so far, Sir Keir has allowed some to deviate by expressing support for a ceasefire in Gaza.
But the Labour spokesman said that “space” for debate did not extend to a vote in Parliament because “that has a significance to it that everybody understands”.
