Sir Keir Starmer stands ready to sack any Labour frontbenchers who defy him in the Commons over a Gaza ceasefire.
While backing humanitarian pauses, the opposition leader says a ceasefire would only allow Hamas time to regroup.
But he has so far allowed shadow ministers to express their anger at the punishing impact on Palestinian civilians from Israel’s ground offensive.
However, his tolerance will end if Labour shadow ministers act on their frustration by voting in Parliament. A potential flashpoint looms next week after supporters of a ceasefire tabled an amendment to the King’s Speech in the House of Commons.
Speaker Sir Lindsay Hoyle has yet to say whether he will allow the amendment brought by the Scottish National Party.
A separate and symbolic “Early Day Motion” urging a ceasefire has attracted dozens of signatures, mostly Labour left-wingers.
Bradford East MP Imran Hussain signed the motion after quitting his role as shadow minister for the new deal for working people on Tuesday, becoming the first Labour Labour frontbencher to resign over the Gaza crisis.
“Look I think it is right to give people the ability to interpret the very difficult situation on behalf of their constituents,” shadow business secretary Jonathan Reynolds told Times Radio.
But he stressed: “Of course within Parliament, when you have a clear Labour, opposition front-bench position, you can’t engage in (dissenting) parliamentary activity, whether that’s voting or any other measure.”
No other frontbenchers have yet joined Mr Hussain but three members of Haringey council, the town hall in shadow foreign secretary David Lammy’s constituency, have resigned to form an “Independent Socialist Group”.
Four shadow ministers are prepared to quit in the coming days and up to 10 others are on “resignation watch”, the Guardian reported.
Bradford West MP Naz Shah, who is a shadow Home Office minister, dabbed at her eyes with a tissue after speaking from the backbenches on Wednesday about the “heartbreaking” plight of children in Gaza.
In Wales, a ceasefire motion was passed last night in the Senedd after ministers in the Labour-led devolved government abstained and backbenchers were offered a free vote.
