The revolt is growing. The first cracks in the fragile shadow cabinet unity over Sir Keir Starmer’s backing for Rishi Sunak in the Israel-Hamas conflict are starting to appear.

Shabana Mahmood, the shadow justice secretary, has written a letter to constituents suggesting Israel may be guilty of “collective punishment” of “the innocent civilians of Gaza”.

She’s not, it must be said, joining the growing number of rebel Labour MPs and councillors, together with big beasts Sadiq Khan, Andy Burnham and Anas Sarwar, who are calling for a ceasefire.

But now that dissent in the party is beginning to reach the shadow cabinet, which until now has been loyal and solidly behind Sir Keir over his refusal to back a ceasefire, the Labour leader should be worried.

In fact, Mahmood – along with ultra-loyal Wes Streeting, the shadow health secretary – is reported to have privately warned Sir Keir that Labour risks sounding callously indifferent to the suffering in Gaza.

The mutiny began after an LBC radio interview in which, on top of his reluctance to support a ceasefire, Sir Keir appeared to back Israel’s right to withhold water and electricity from Gaza, provoking an angry backlash.

He later apologised and said he hadn’t meant to give that impression. But the damage had been done. You could say, therefore, that the Labour leader has only himself to blame for the growing mutiny.

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‘Heartbreaking’

Loyalist Shabana Mahmood, one of the UK’s first Muslim women MPs, represents Birmingham Ladywood, former constituency of Labour firebrand Clare Short, where more than 40% of the population are of Asian descent.

In her letter to constituents, seen by Sky News, she says the humanitarian crisis in Gaza is “heartbreaking” and calls herself “a determined and life-time supporter of the rights of Palestinians”.

And she writes: “Like thousands of my constituents that have been in touch, I share the upset and concern of you all as we witness the destruction and displacement of human lives on a horrific and unprecedented scale.

“The killing of innocent civilians in Gaza must stop immediately.”

Nothing particularly controversial or critical of Sir Keir there. But then she adds, more controversially, that the innocent civilians of Gaza “do not deserve collective punishment”.

That’s a phrase that was used in Prime Minister’s Questions last week by rebel front bencher Yasmin Qureshi, MP for Bolton South East, where a fifth of residents are of Asian descent.

As MPs listened in silence, Qureshi quoted an email from a constituent with a relative in Gaza, who pleaded: “My heart can’t handle this anymore. We are being massacred, relentlessly bombed. Homes destroyed. No water, no food, no electricity.”

And in a question that seemed directed more at the Labour leader than the PM, she said: “How many more innocent Palestinians must die before the prime minister calls for a humanitarian ceasefire?”

Qureshi, who has previously criticised Israel’s treatment of the Palestinians, is one of around a dozen junior front benchers who have challenged Sir Keir’s position on the Israel-Hamas war.

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Most have large Muslim communities and in most cases the MPs have reposted online messages or statements calling for a ceasefire or sympathetic to the Palestinians’ plight.

The most high-profile of these MPs is Jess Phillips, another Birmingham MP, and they also include Bradford MPs Naz Shah and Imran Hussain and London MPs Andy Slaughter and Rushanara Ali.

For example, as well as re-tweeting others, Phillips tweeted this weekend: “You cannot tell people who have nowhere to go to leave for their safety. It’s merely a gesture to appease.”

Some of Sir Keir’s critics have claimed his stance could cost Labour up to 30 seats at the next general election, a claim that’s disputed by his allies. But there’s no doubt Labour MPs with a big Muslim community are seriously worried.

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On Sunday Morning with Trevor Phillips on Sky News, Sir Trevor suggested to shadow cabinet loyalist Peter Kyle that Sir Keir was determined to “shake off the taint of antisemitism”.

“So you’ve got to back Israel, come what may, and you’ve made a cold calculation that the votes of Muslims, that you might lose three million or so voters won’t matter as much as getting back the votes that you lost because of the Corbyn era?” he said. “In short, you’re taking Muslim votes for granted?”

Not surprisingly, that suggestion was firmly rejected.

“We’re not thinking how do we win votes or what votes we lose, at a time when there is war and conflict unfolding before us and there are human tragedies of a scale we’ve not seen for a very time,” Kyle replied.

But the longer the Israel-Hamas conflict goes on and the civilian death toll and suffering become even more horrific, Sir Keir may need to think again and bow to pressure to listen to his rebels.

And not just the rebels on the back benches. But, more significantly, those voices inside the shadow cabinet who now appear to be more prepared to challenge his position.

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