Sir Keir Starmer is braced for resignations from his frontbench as he holds a difficult vote on the Israel-Gaza war.
It does not call for a ceasefire, as dozens of Labour MPs – including members of the frontbench – have demanded.
However, the amendment is intended to move closer to this position, by calling for “longer” humanitarian pauses in fighting to allow in aid, which shadow minister Lisa Nandy conceded could be days or even weeks.
A senior figure told Sky News the wording suggested “a ceasefire in all but name”, although Labour rejected this.
The amendment also condemns the conduct of the war by both sides; and highlights the need to protect hospitals from attacks, as well as calling for Israel to end its siege of the territory.
It unequivocally condemns the terrorist attacks on 7 October and says Israel has a right to defend its citizens from terrorism.
Those calling for a ceasefire include 19 shadow ministers and aides, who must back the Labour Party’s position.
Labour sources said any who voted for a separate amendment from the Scottish National Party backing a ceasefire would have to resign or face the sack.
They are not all expected to resign, and the shadow cabinet – Sir Keir‘s top team – are all expected to back the amendment.
Meetings were going on late on Tuesday night to talk around some of those wavering.
One shadow minister, Imran Hussain, has already resigned. Others on resignation watch include shadow home office ministers Jess Phillips and Naz Shah.
Some Labour backbenchers have vowed to back other amendments which do call for a ceasefire.
Sir Keir explained his position in a speech two weeks ago, saying he understood the strong feelings many had for a ceasefire, but that it was the wrong decision as it would “embolden Hamas” and allow them to regroup and carry out more horrific attacks like those on 7 October.
But he has faced intense pressure from some of his MPs, who have been horrified by the scenes unfolding in Gaza, where Israel is carrying out a military campaign to destroy Hamas.
Shadow foreign secretary David Lammy, when he addressed MPs on Tuesday in the House of Commons said, in a shift in tone: “Israel must make changes to the way it is fighting this war, by taking urgent, concrete steps to protect civilians”.
At a difficult meeting of the parliamentary Labour Party on Monday night, Sky News understands a number of MPs spoke out.
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One MP later said: “The leadership have been slow to realise the scale of this. They thought it was the very left of the party, and MPs with a lot of Muslim constituents, but it’s an issue for a lot of our liberal voters too.
“They see pictures of premature babies dying because Gaza’s hospitals can’t run the incubators, and they want us to be taking a different position.”
The MP said there was an understanding that implementing a ceasefire on the ground could take weeks to broker.
A Labour spokesperson said: “Labour’s amendment reaffirms the position set out in Keir Starmer’s Chatham House speech and reflects our concerns about what we’ve seen on the ground in the last fortnight which includes the lack of hostage release, the insufficient amount of aid and utilities getting in and being distributed, the scale of civilian casualties in Gaza and the amount of violence on the West Bank.”