Sir Keir Starmer has lost eight frontbenchers after he suffered a major rebellion in a Commons vote calling for a ceasefire in Gaza.

Four shadow ministers, including Jess Phillips, Yasmin Qureshi, Afzal Khan and Paula Barker, quit on Wednesday evening after deciding to support an SNP amendment to the King’s Speech backing a ceasefire.

Four other frontbenchers: Rachel Hopkins, Sarah Owen, Naz Shah and Andy Slaughter; have also left the front bench after breaking the party whip to back the amendment.

Parliamentary private secretaries Dan Carden and Mary Foy have also left their positions.

MPs voted 293 to 125, majority 168, to reject the SNP’s King’s Speech amendment calling for “all parties to agree to an immediate ceasefire” in Gaza.

But 56 Labour MPs backed the position, rejecting their party leader’s stance.

Labour MPs had been ordered to abstain on the SNP move and were told instead to back Sir Keir’s position calling for longer “humanitarian pauses” rather than a ceasefire.

In a statement following the vote, Sir Keir said he regretted that party colleagues had not backed his position.

“Alongside leaders around the world, I have called throughout for adherence to international law, for humanitarian pauses to allow access for aid, food, water, utilities and medicine, and have expressed our concerns at the scale of civilian casualties.

“Much more needs to be done in this regard to ease the humanitarian crisis that is unfolding in Gaza.

“And in addition to addressing the present, every leader has a duty not to go back to a failed strategy of containment and neglect, but to forge a better and more secure future for both Palestinians and Israelis.

“I regret that some colleagues felt unable to support the position tonight. But I wanted to be clear about where I stood, and where I will stand.”

Ms Phillips, a high-profile frontbencher, said it was with a “heavy heart” that she was quitting.

“I have tried to do everything that I could to make it so that this was not the outcome, but it is with a heavy heart that I will be leaving my post in the shadow Home Office team.

“On this occasion I must vote with my constituents, my head, and my heart which has felt as if it were breaking over the last four weeks with the horror of the situation in Israel and Palestine,” she said in a letter to her party leader.

Some of the MPs had signalled their intention to break with Sir Keir in the Commons debate preceding the vote, after already having called publicly for a ceasefire.

Ms Shah warned of a “humanitarian catastrophe”, while Mr Khan told the chamber that his “constituents have demanded” a ceasefire.

The scale of the rebellion will be a blow to Sir Keir, who had hoped to avoid further damaging splits within his parliamentary party over the issue.

The party has been riven with internal divisions over Israel’s response to the deadly incursion by Hamas that sparked the conflict.

The leadership has backed 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 has stopped short of calling for a total cessation of hostilities.

Several of the frontbenchers made clear why they believed Sir Keir’s stance was wrong.

Ms Qureshi, who represents Bolton South East, said: “The situation in Gaza desperately requires an immediate ceasefire to address the humanitarian catastrophe and to advance moves towards a political solution that brings freedom, prosperity and security.”

Some in Labour had accused the SNP of intentionally using the amendment to exploit divisions in the party.

But SNP Westminster leader Stephen Flynn said that his MPs “will be able to look themselves in the mirror knowing they did the right thing”.

“It is clear that support for a ceasefire would have been even stronger tonight if Keir Starmer had not threatened Labour MPs with punishments if they voted for peace,” he said.

Peter Kyle, the shadow science secretary, defended the decision to impose a strict three-line whip for the amendment rather than allowing a free vote.

“Just because it’s an international policy doesn’t mean that it’s not a policy that we should stick together on as a team,” he told ITV’s Peston programme.

“We’ve seen Keir engaging with people from all communities, all traditions within the Labour Party. He has allowed people to speak out on these issues. So we have allowed as a party a very broad debate.

“But there are key times, if you are the party that seeks to run the country and you want to be the prime minister of our country standing on the international stage, where you have to show that we are a united party that can resolve itself in Parliament and the government.”