Video report by ITV News Political Correspondent Daniel Hewitt
Pressure is growing on Henry Bolton to leave his position as Ukip leader and the resignation of six key party figures following the vote of confidence against him.
Ukip's ruling committee unanimously backed a vote of no confidence and the party's deputy leader, immigration spokesman and trade and industry spokesman have all stood down form their roles, citing the fact they could not work under Mr Bolton.
The party's deputy leader, Margot Parker MEP, quit on Monday, telling Mr Bolton to relinquish the leadership in the process.
Ms Parker's announcement was quickly followed by immigration spokesman John Bickley confirmed he would not continue in his role under the current leader.
A third resignation came as trade and industry spokesman William Dartmouth MEP, confirmed he would be standing down, too.
Ukip's assistant deputy leader Mike Hookem joined the exodus saying he had lost the support of MEPs, party staff and grassroots members.
Ukip's education spokesman David Kurten has quit over Henry Bolton's leadership of the party.
The London Assembly Member said: "It is time for him to step down with dignity rather than extending the current debacle for another four weeks.
East of England MEP Tim Aker quit as local government spokesman, saying he hoped leader Henry Bolton "does the right thing" and resigns.
Mr Bolton, whose leadership of the party was called into question following revelations that his girlfriend Jo Marney sent racist text messages, told ITV's Peston on Sunday that Ukip could not survive another leadership contest.
He told Robert Peston that if the party's national executive committee (NEC) "decides to go down the route of months of further infighting and further negative media scrutiny by deciding to pass a vote of no confidence in me, then I think that the reality is that the party is probably over."
But hours later, the NEC did just that, with a Ukip spokesman announcing: "The vote was carried unanimously with the exception of the leader."
That means party members will now be given a vote on whether the former army officer should remain in post.
Ms Parker told BBC Northampton: "It would be quicker and cleaner if he came to the conclusion he could go sooner rather than later.
"This is taking time away from doing the job. This puts the party in a limbo situation."
Mr Bickley announced his resignation on LBC, he said: "As Immigration and Integration Spokesman, I will be resigning today. I'm not going to do the job for Mr Bolton."
Mr Dartmouth wrote: “Your personal life has become the entire story.
"The NEC, as well as colleagues on the London and Welsh assemblies and fellow MEPs have all urged you to stand down as party leader with immediate effect. Your position is untenable. I am unable to serve under you.”
If Mr Bolton is forced out, Ukip will have lost its fourth leader in 18 months.
Asked if Mr Bolton's claim about the party's possible collapse was correct, Paul Oakden, the party's chairman, said: "I think it's absolutely true that the party is now facing another challenging time, however, there is great strength of feeling on this particular issue [on] both sides of the fence."
Many of Mr Bolton's colleagues have expressed concern over his judgement - Ukip Treasury spokesman Jonathan Arnott left the party in protest at Mr Bolton's leadership on Friday saying it had become "abundantly clear" he was not the right person for the job.
Ms Marley posted a tweet on Sunday demanding the NEC let Mr Bolton "get on with his job."
Speaking on Peston on Sunday earlier, Mr Bolton reiterated that he did not condone "in any way" Ms Marney's comments - which included saying Prince Harry's fiancee Meghan Markle's mixed-race background would "taint" the royal family - but said he planned to stay on as party leader.
"We've got to focus on the May [local] elections and we need to get the party fighting fit to deliver its politics into the Brexit debate, and what happens post-Brexit," he said.
Mr Bolton broke up with Ms Marney after her comments came to light and has tried to distance himself from the 25-year-old model. But they have since been photographed together.
Asked if the relationship was "definitively over" he said: "We're still in touch."
He said the two of them planned to put evidence to the NEC that would show that "within the party there are subversive elements" seeking to undermine Mr Bolton and the party.
Ms Marney, whose party membership was suspended as her comments about Ms Markle were published, resigned from Ukip on Saturday, according to the Mail on Sunday, after being presented with more evidence of offensive messages.
Mr Bolton left wife Tatiana, 42, who gave birth to their second daughter at London's St Pancras station in 2016 after going into labour on a train, prior to his relationship with Ms Marney becoming public in early January.