Jeremy Corbyn was accused by supporters of “undermining his own people” after crushing Labour members’ attempts to get the party to campaign to remain in the EU.

“Embarrassed”, “angry” and “depressed” Corbyn supporters used a secret meeting to hit out at the leader’s “bunker mentality” and warned the party was “haemorrhaging” votes to the Liberal Democrats and Greens by staying neutral on Brexit.

At an impromptu debrief hosted by the pro-Remain Another Europe Is Possible group and attended by Corbyn allies, including shadow minister Clive Lewis and author Paul Mason, several members said the leader had betrayed promises to empower members and usher in a kinder, gentler politics.

And they ended the meeting by chanting “stop Seamus Milne”, Corbyn’s divisive strategy director who many blame for the party’s “triangulation” on Brexit.

Corbyn on Tuesday night won support from the party’s conference for his plan to delay a decision on how to campaign in a second referendum until after a Labour government has negotiated a new “soft” Brexit deal with the EU.

But there were fractious scenes in the hall in Brighton after National Executive Committee (NEC) chair Wendy Nichols refused to call a detailed card vote and instead relied on a show of hands after consulting with general secretary Jennie Formby, a close ally of Corbyn.

Several sources told HuffPost UK they believed the leadership wanted to avoid a card vote as it would have revealed an embarrassing split between ordinary members, a large proportion of whom back Remain, and union blocs which backed the leadership.

Many described it as a “stitch up” of members.

Immediately after the vote, pro-Remain Corbyn-supporting members headed to the basement of a Brighton pub to chew over their controversial defeat.

One said: “The people that we dealt with today, they weren’t the people that we had as opponents in the conference immediately after Corbyn’s selection. These were people that we’ve been through all these fights with, like fellow Corbynistas, for want of a better term, and they’ve got a bunker mentality. 

“And we all recognise that bunker mentality, because we’ve sat there for three years going ‘fuck off’ with baseball bats, and they are still doing it.

“They don’t recognise that the world has moved on, but something is going to happen that is going to blow up that bunker mentality.”

One female member criticised some members’ attempts to turn the vote into a test of loyalty to Corbyn, urging colleagues to “trust” him on the party’s tactics.

“The only argument they could make was loyalty to the leader, there was no argument at all,” she said.

“It was emotional, tribal and very male,”

“There were these kind of hectoring men who were telling us we had to fall in line with the leadership.”

She likened the play by the leadership to the days of “stage managed” conferences under Tony Blair, saying Corbyn had “lost the idea of a democratic party”.

“It is so deeply depressing that the Corbyn machine seems to have taken over so much and taken us over in less effective ways and ways that have actually undermined Corbyn’s own people,” she said.

Another member warned Labour was losing votes to the Lib Dems and Greens in the constituency where he used to work for an MP.

“I haven’t been as embarrassed and angry as I have been today with the Labour party, in any way, since I first joined the Labour party,” the member said.

“I’m really pissed off, because I voted for Corbyn both times, and I did it because I love the policies and I believe in a fairer kind of politics, that’s what I was sold on.

“What happened today wasn’t a kinder politics. It wasn’t a gentler politics. It was the arm bending of the members of this party by the top echelons of the leadership. 

“And it isn’t right and it shouldn’t happen.” 

Another member made clear pro-Remainers’ determination to fight another day, with organisers suggesting the movement was the beginning of a “new left tendency” in Labour, bringing together members of the Corbyn-backing Momentum group and internationalist left.

“I think we need to create a seriously organised, like seriously organised movement in branches, because I know that the authoritarian left is seriously organised, you can just tell, so we need something really serious, and that’s going to step in and take over when this all goes to shit, because it will,” she said.