A major stand-off has developed between senior UKIP figures and the party's only MP over public money they are entitled to receive.
UKIP is entitled to around £650,000 of what's known as Short money which goes to opposition parties to help finance their backroom operations.
Douglas Carswell was approached by UKIP's party secretary on Monday and asked to recruit 15 extra staff for his parliamentary office.
The Clacton MP rejected the proposal.
He made it clear he was not going to agree to the plan which sources close to him have described as "improper".
It is also believed the Essex MP thinks spending that amount of taxpayers' money is "not what we're about".
Details of the dispute were made public by UKIP party officials following Mr Carswell's refusal to agree, I understand.
Mr Carswell told the BBC "I am not a US senator", adding: "I don't need 15 staff".
"UKIP is supposed to be different," he explained.
A party with just one MP and there are serious splits, almost unbelievably.
On the one hand, you've got a principled row between Douglas Carswell and other senior figures. He doesn't want to take the money, but some figures at the top of the party believe they need the money and they should take it.
On the other, there's something quite nasty going on in private between Carswell and one senior figure close to Farage, briefing against each other. I think there's some dishonest versions of what's going on and it's all quite nasty.
Explainer: What is Short money and how much do parties get?
A senior UKIP official close to Nigel Farage has accused the MP of "absurd" and "improper" behaviour, telling the BBC Mr Carswell sent an email on Monday saying he wanted sole control of the £650,000.
The source suggested this was an "improper" proposal, saying that the party planned to give Mr Carswell staff but added "at no point have we said what we expect him to do".
The senior party staffer said: "This is him throwing his toys out of the pram because he thought Nigel wouldn't be leader any more."
UKIP has insisted that the public funds will go to the party irrespective of Mr Carswell's views, saying they've "triple, quadruple checked that".
The source said "it's for us to spend as we want to spend it" and they added that "the party will take a dim view of four million people going unrepresented" if the Essex MP refuses to accept some of the money.
But Mr Carswell said Nigel Farage would back him in the row and he was "very pleased" that Mr Farage was still the party leader.
What is Short money?
"Short money" is an annual payment to the opposition parties in the Commons to help them with the costs incurred in performing their parliamentary functions.
It takes its name from former Labour MP Ted Short who was instrumental in its introduction as leader of the House of Commons in 1974 and 1975.
It is meant to create more of a level playing field for opposition parties, who, unlike the governing party, do not have access to civil servants to help them research policies.
The amount payable to qualifying parties is £16,689.13 for every seat won at the most recent election plus £33.33 for every 200 votes gained by the party.
"I'm absolutely certain that Nigel will agree that this is the right thing to do.
"I'm certain that one or two excitable staffers in the cold light of day will recognise that their proposal was quite wrong, and I am quite certain there will be agreement on this.
"All of those people who voted for us because they want political change will recognise that here at last is a party that's prepared to practice what it preaches.
"I am very pleased indeed that Nigel is party leader, and I think the success we had in the recent elections - four million people voting for us - is extraordinary"
Senior UKIP figures rushed to defend Mr Carswell on Twitter.
MEP Patrick O'Flynn tweeted: "Whoever is briefing against @DouglasCarswell does not have UKIP's best interests at heart. Idea he would do anything 'improper' is absurd."
His message was echoed by fellow MEP Steven Woolfe, who tweeted: "Those briefing against @DouglasCarswell must stop. He is a man of integrity and honour and that is to be respected."
Mr Farage has, meanwhile, suggested he could contest a by-election in a Labour-held seat.
He had promised to quit if he failed to win a seat at the general election, but had his resignation rejected by his party.
He told BBC Radio 5 live: "I would look forward to a by-election in a Labour seat very much indeed."
He also said he had sat in a "darkened room" before deciding to continue.
Mr Farage failed to be elected in South Thanet, losing out to the Conservative candidate.