The end for UKIP? Anti-EU party prepares for 'make or break' leadership vote

In that period the party has waved goodbye to its talisman Nigel Farage, had four different full-time leaders, came perilously close to a takeover from the far right, and seen its national vote crumble.

Tomorrow members will hold an extraordinary general meeting (EGM) in the West Midlands to decide on the future of embattled leader Henry Bolton, whose turbulent four month reign has stoked party divisions.

And while UKIP hasn't quite broken yet, even the most dyed in the (purple) wool members admit the vote is pivotal for UKIP's future.

"If Bolton wins then you will see members quit en masse. We could lose half of our membership almost overnight," said Bill Etheridge, himself a veteran of three leadership battles.

The West Midlands MEP and Sedgley councillor is one of dozens of elected 'Kippers to call for Mr Bolton to step down after his girlfriend, Jo Marney, was revealed to have sent racist texts about Meghan Markle.

The scandal led to UKIP's national executive committee (NEC) passing a vote of no confidence in Mr Bolton last month, a decision which prompted tomorrow's EGM.

There are two possible outcomes from the meeting. Either Mr Bolton keeps the job he has steadfastly refused to relinquish, or he is voted out and the party will begin yet another search for a leader.

Despite supporting Mr Bolton in UKIP's most recent leadership contest last September, Mr Etheridge is unequivocal in his view of his suitability for the role.

"He has shown himself to be completely out of his depth, has no political convictions whatsoever and appears to lack principles," he said.

"UKIP is not likely to be in government anytime soon, but at the very least we should be pushing the framework of debate. That hasn't happened under the current regime."

Mr Bolton, a former Liberal Democrat parliamentary candidate who defected to UKIP in 2014, has been at war with the NEC almost since he took over.

He has unveiled plans to reduce the power of the 14-strong group in a bid to reform the party – a move backed by Mr Farage, who has derided the NEC as 'a group of volunteers, who frankly had no political experience at all'.

If Mr Bolton gets his way, the decision making power will shift from the NEC to party leader.

His new constitution also proposes the leader should get paid by the party if they are not in an elected position, and members could be kicked out if the do anything that 'is liable to undermine the cohesion and unity of the party'.

This year Mr Bolton has seen the resignations of a series of top figures from his frontbench, including Mr Etheridge, deputy leader Margot Parker, Gerard Batten, Mike Hookem and Dudley councillor Star Anderton.

This week party chair Paul Oakden announced he would step down after the EGM, a decision he says has nothing to do with the party's current troubles, while former general secretary Jonathan Arnott has also quit.

Last year six committee members of UKIP’s Sandwell branch resigned after accusing the party's leadership of failing to address issues affecting the borough.

Mr Bolton insists he has received a 'huge amount of support' from around the country. Asked recently if his leadership was over, he said: “No, I don’t believe it is.”

Should he be voted out tomorrow, an interim leader will be elected for 90 days prior to a new leadership election.

Unsurprisingly, the candidate list is likely to feature some familiar faces from previous leadership contests.

They include UKIP founding member Mr Batten, David Kurten, former deputy leader Peter Whittle, and Mr Etheridge.

Tomorrow's vote is open to all of UKIP's membership – estimated to number around 24,000 – although members must have registered in advance and be present at the EGM at Birmingham's ICC to place their vote.

Mr Etheridge says he will be arriving early at the venue to hand out letters explaining 'exactly why Bolton needs to go'.

"At the moment it is very much in the balance whether he wins or gets booted out," he said.

"Of all the party votes we have had in recent times, you could argue that this is the most important one of them all."