Labour's top team has been warned not to oppose Jeremy Corbyn over military action in Syria after the party leader said he could not support RAF air strikes against Islamic State (IS) extremists.
Diane Abbott - one of Mr Corbyn's few allies in the shadow cabinet - said Labour MPs who backed David Cameron over air strikes would put themselves at odds with grassroots party members.
Her intervention came as the rift between Mr Corbyn and the majority of his shadow cabinet spilled out into the open after the Labour leader said the Prime Minister had failed to make a "convincing case" for further military intervention against IS.
His comments were in sharp contrast to those of shadow foreign secretary Hilary Benn, who said Mr Cameron had made "compelling arguments" when he set out his case for extending air strikes against IS into Syria in a Commons statement.
After a 90-minute meeting of the shadow cabinet to discuss their response failed to reach an agreement, shadow ministers will gather again on Monday in an attempt to thrash out an common position.
Ms Abbott, the shadow international development secretary, warned that those who supported air strikes - said to be the overwhelming majority of the shadow cabinet - could expect to come under pressure from local activists when they return to their constituencies at the weekend.
"I am sure that people will go home, they will talk to their friends, they will talk to their constituents and we'll make the final decision on Monday. I am confident that it will be the right decision," she told Channel 4 News.
She added: "He (Mr Corbyn) is the one with the electoral mandate, he appoints the shadow cabinet - not the other way round. I know what views party members will take if MPs ignore the views of the people at the grassroots and try and take this issue to the brink."