Nigel Farage has dismissed a bitter row over his leadership of Ukip as 'people letting off steam', insisting a leadership contest would be a 'massive, massive mistake'.

After resigning the leadership a week ago only to back out of the decision at the urging of the party executive committee three days later, Mr Farage told a BBC Question Time audience that changing leader would be wrong with an EU referendum looming.

Mr Farage had promised to resign the leadership if he lost the Thanet South constituency at the general election and followed through on his pledge within minutes of defeat being confirmed. The U-turn came after party officials said he retained strong backing from party members.

The events prompted MEP Patrick O'Flynn, the party's economic spokesman, to accuse him of turning Ukip into a 'personality cult' and becoming a 'snarling, thin-skinned, aggressive' man.

On Question Time, Mr Farage said: 'I was disappointed that a member of our team said this, but look, general elections you're under a huge amount of pressure and particularly it's like a boiler room, a pressure cooker.

'I'm sure the others would agree, and we maintained discipline as a party extraordinarily well during this general election compared with the past. The election's over, people are letting off steam, and we've seen one or two people fighting personal wars against each other.'

He added: 'The level of support for me in the party is phenomenal and frankly, to go through a leadership contest at a time when Mr Cameron says he's renegotiating our relationship with the European Union, would be a massive, massive mistake.'

Mr Farage said he expected the referendum to be as soon as May 2016 meaning 'for UKIP to spend three months on a leadership campaign would have been a huge mistake'.

The Ukip leader's comments came after the party attempted to portray a rallying of support, producing a series of supportive statements from senior figures and donors.

But Mr O'Flynn defended his remarks to The Times while donor Stuart Wheeler insisted Mr Farage should quit again.

Mr O'Flynn told the Press Association: 'I may well have burnt my bridges but it had to be said.

'I'm not in politics to pursue personal seniority but to persuade the British public that we are good enough to govern ourselves away from the EU.'

He added: 'There are a couple of advisors who are pushing Nigel in the wrong direction both in terms of policy and style of leadership.'

Spread betting tycoon Mr Wheeler, a former party treasurer who donated almost £100,000 to help fund Ukip's general election campaign, had earlier escalated the row after Mr O'Flynn's comments. He told BBC Radio 5 Live that Mr Farage should go .

He said: 'I would like him to step down, at least for the moment. And if he wants to put himself up in an election, then he has every right to do so, though I personally would prefer somebody else now.'

Mr O'Flynn's explosive intervention prompted Mr Farage's outgoing chief of staff, Raheem Kassam, to call for his resignation.

Mr Kassam was one of two Ukip staffers highlighted by Mr Flynn as damaging Ukip.

Mr Kassam is on holiday until his election contract expires at the end of May, when he plans to leave Ukip and return to journalism.

He told Sky News: 'You cannot go to a national newspaper and air internal party grievances as an elected representative of the party. It is wholly unprofessional and I think Patrick should absolutely consider his position.

'I have no problem with him as a bloke, I think he's a nice chap, he has some good ideas. But unfortunately over the last 24 hours he has shown himself to be utterly unprofessional and undeserving of holding that title and holding a spokesperson role for the party.

'I think Patrick should take some time out - I know he has some issues he has to deal with, I feel for him.'

The rapidly escalating row prompted Ukip to issue a series of statements from senior figures which were supportive of Mr Farage.

Former Ukip leader Lord Pearson said: 'Nigel fought a brilliant election campaign and what an achievement it was to get nearly four million votes. Nigel has my full support as leader.'

Richard Desmond, the owner of Express Newspapers who donated £1 million to Ukip during the campaign, said: 'Nigel has my support 101%.'

Ukip's deputy leader Paul Nuttall said: 'The general election was a great success, delivering four million votes in the bag. The 2020 vision is on course.

'Ukip have the best communicator in British politics leading this party and who will play a vital role during the referendum campaign.'

In the background of the row over party leadership, Ukip is involved in a stand-off with its only MP, who is resisting pressure from the party to claim £650,000 a year of taxpayers' money to fund up to 15 additional members of staff.

Douglas Carswell has insisted he will not claim the full amount but denied rumours that he was set to quit Ukip - a move which would block the party from claiming the money.

'I am 100% Ukip,' he said. 'I am staunchly and proudly Ukip.'