Conor McGinn and Holly Lynch believed to be among those on verge of resigning over Jeremy Corbyn’s dismissal of long-serving chief whip

The Labour party is to be thrown into fresh chaos as several of its whips, in charge of party discipline and voting, are set to walk out of Jeremy Corbyn’s shadow team in response to the surprise sacking of the party’s chief whip.

Those understood to be on the verge of resigning over the dismissal of Rosie Winterton include Conor McGinn, the MP for St Helens North, and Holly Lynch, the MP for Halifax. Winterton’s sacking and the manner in which it was done on Thursday has caused widespread fury among MPs, including among those previously supportive of the Labour leader.

Corbyn’s decision to speak at an anti-racism rally linked to the Socialist Workers party (SWP) on Saturday also caused huge consternation with even prominent supporters Owen Jones and Aaron Bastani criticising the decision on social media.

Winterton, who has held the post of chief whip since 2010, had to ask for a face-to-face conversation with Corbyn as he tried to dismiss her on the phone after six years of service, according to her parliamentary allies.

It is understood that she was “shocked” at the attempt to oust her from the post by telephone and suggested that the Labour leader explain his decision in person.

“She was obviously hurt,” said one friend. “She got the call from Corbyn on Thursday afternoon. He offered her another job, but she said no and that it sounded like he wanted to sack her. Rosie said to him, ‘I think we should have a conversation in person’, which then took place.”

The resignations from the whips’ office are expected to come by Monday. However, it is understood that Winterton’s dismissal has had wider repercussions, with a number of prominent figures who had been tempted to return to the shadow cabinet being put off.

Dan Jarvis, the MP for Barnsley Central and a rising star, was expected to be appointed to a senior post, but the absence of any announcement relating to him was notable.

“Just on a practical level, it was bad politics,” said one senior Labour source. “If they had sacked her at the end, they would have had a much stronger shadow cabinet. People who were going back decided not to go back. People are shocked and angry.”

A former shadow cabinet member added: “It was the Rosie thing – and that it was clear that Jeremy was just looking to fill empty chairs rather than form a shadow cabinet of all the talents – that put people off.”

One senior Labour source said Winterton, who was made a dame in the last New Year’s honours list, had a reputation for being one of the most discreet and loyal of the shadow team, working behind the scenes to try to keep Labour’s warring groups together.

“She more than anyone tried to keep things together over the summer, coming up with plans about how to unite the shadow cabinet and the party,” the source said. “She has really tried to make it work.”

However, a current member of Corbyn’s shadow team claimed that Winterton had also allowed Corbyn to make serious mistakes, including a previous reshuffle that went on for weeks. “Jeremy tried to sack Rosie when he was first made leader,” the source said, “but the rest of the whips threatened to quit. So he has done it when he is stronger, and I think he is quite within his rights.”

Winterton, who in March was identified on a list of MPs compiled by allies of Corbyn as “hostile”, has been replaced as chief whip by Nick Brown. It is understood that Brown, who served in the role under former prime minister Gordon Brown, insisted that he would only take the role if the rest of the whips’ office remained in post.

Facebook Twitter Pinterest Nick Brown replaced Winterton in the reshuffle. Photograph: Carl Court/PA

However, concerns have been raised by senior figures in the party that Brown, who lost his post when Ed Miliband won the leadership, is not aware of the scale of the task facing him. “Nick has in reality been semi-detached from parliament in recent years. He was chief whip in government,” said one. “This will be very different, as liked as he is.”

Corbyn is expected to face criticism at Tuesday’s meeting of Labour’s national executive committee over the removal of Jonathan Ashworth from the party’s governing body in favour of loyalist Kate Osamor, at a time when those on the committee had asked the leader to be conciliatory. Ashworth was given the health brief but removed from the NEC. Senior party sources said Corbyn’s right to remove Ashworth from the NEC would be challenged. Such a decision is supposed to be made after consultation with the wider shadow cabinet.

On Saturday the former home secretary Alan Johnson said he had decided to keep his counsel on the future of Corbyn. When it was put to him on the BBC’s Today programme that he believed Corbyn was not up to the job, he said: “Me and many of my colleagues: perhaps he’ll prove me wrong.”

Johnson’s assessment came as the chairman of the parliamentary party, John Cryer, condemned Corbyn’s controversial shake-up of his top team during a period when the leader’s office had been in talks about the shadow cabinet being elected in part by MPs.

Shadow foreign secretary Emily Thornberry defended Corbyn, saying it was wrong to criticise him for being “too decisive” and insisting that the issue of elected posts was still on the table.

She said: “It’s not a question of ‘forget all that’: there are negotiations going on. There’s an NEC away-day in which this issue is going to be discussed as part of a larger package in terms of making sure that the party is more democratic, and these negotiations are ongoing.

“What do you want? The problem is that on the one hand people criticise, and have been criticising, Jeremy for being weak, for taking too long on his reshuffles, taking a couple of days, and yet when he decides that he will do a reshuffle that he needs to do in order to fill vacancies and in order to reach out, people then criticise him for being too decisive and too strong.”

A spokesman for Corbyn said the Labour leader attended a Stand Up to Racism event on Saturday co-convened by a senior member of the SWP as he “wanted to show his support for the campaign against racism and xenophobia, particularly given the rise in hate crime since the EU referendum in June”. Claims from Jones, and others, that the event was organised by a front organisation for the SWP were denied.

