UKIP’s National Executive Committee (NEC) has declared UKIP MEP and leadership favourite Steven Woolfe “ineligible” to stand in the up-and-coming contest.

The NEC claimed he is “ineligible as a result of a late submission”. It has also been claimed that he failed to renew his party membership and to declare a drink driving conviction when he stood and a Police Crime Commissioner in 2012.

Two of the three voting members of the NEC selected for the panel have expressed private opposition to Mr Woolfe’s candidacy, according to sources close to Mr. Woolfe, and some members are accused of having private connection to rival candidates.

Three other members of the NEC – Victoria Ayling, Mick McGough and Ray Finch – have promptly resigned in protest of Mr. Woolfe being blocked.

In a joint letter, they said members of the NEC had placed “personal ambitions, loyalties and jealousies at the heart of their decision-making” and displayed an “escalating megalomania”.

Mr. Woolfe claimed in a statement that the NEC “has proven it is not fit for purpose and it has confirmed many members fear that it is neither effective nor professional in the way it governs the party.

“The NEC panel have even accepted they were wrong to raise questions of my membership of the party, as I have been a full member since 2011”.

He also said that “highly confidential information about me held in party documents has been leaked to the press and the NEC have not sought to investigate this gross breach of privacy” and “the NEC’s treatment of Nathan Gill over the past two weeks has also been totally unacceptable”.

“If I were on the ballot, I would have fought to reform the internal structure of UKIP including the NEC. UKIP must professionalise and it cannot do that with an unfit NEC”, he added, concluding: “Although I am out of the contest I wish the other candidates well and hope they can show UKIP has a positive, inclusive, patriotic vision for Britain.”

Those who were allowed on the ballot are Diane James, the new frontrunner and a former parliamentary candidate, Bill Etheridge, an MEP, Elizabeth Jones, a deputy chairman of UKIP’s Lambeth branch, Jonathan Arnott, also an MEP, Lisa Duffy, a party organiser, and Phillip Broughton, a former candidate.

Mr. Woolfe, the party’s migration spokesman, became an MEP for the North West in 2014. He has long been seen as the strong favourite to replace Nigel Farage. As a working class lawyer from the North of England, it is thought he can reach out to both ex-Labour voters in the North and Southern Tory voters.

The decision comes after UKIP MEP Victoria Ayling claimed last night that there is “a coup attempt via the NEC by Carswell/Hamilton” to keep leadership favourite Steven Woolfe MEP off the ballot paper.

UKIP donor Aaron Banks levelled the same allegation this morning.

Mr. Woolfe says IT problems meant that he missed the midday deadline to submit his candidacy forms by 17 minutes. He has since produced email evidence suggesting the £5,000 application fee was paid in time.

He told the BBC Radio 4 Today this Monday: “I did feel like I was in a scene from Little Britain’s ‘computer say no’. But at 11.35am yesterday I managed to be on the phone with my bank to prove that the £5,000 had been transferred over.”

The problems demonstrated why UKIP “really do need to professionalise”, he said.

Asked if he would pursue legal action if his application was rejected, he replied: “I hope it wouldn’t come to that. Hopefully they recognise that everybody in the country now sometimes looks at their computer screens and screams at it when something is not working, but we have a system in place that didn’t seem to work properly that day.”