UKIP’s highest ranking official has admitted the party handed complete control of candidate selection in Scotland to MEP David Coburn.

In an email exchange with Scottish office bearers – seen by the Sunday Herald – party chairman Steve Crowther dismissed criticism of the decision, saying: “I’m afraid that is the situation”.

In a series of communications - which were copied to party leader Nigel Farage – Crowther also begged branch chairs who are in full revolt against Coburn’s leadership in Scotland not to abandon the party.

However, several office bearers are expected to quit UKIP before the Holyrood poll on Thursday, which could see Coburn returned as an MSP for the Highlands and Islands.

The party’s democratic decision-making functions in Scotland were suspended by the London-based party hierarchy in 2013 during a period of infighting - meaning members were unable to vote for candidates to stand for the Scottish Parliament on regional lists.

Coburn said publicly that Holyrood candidates would be selected and ranked by an assessment team led by UKIP director Paul Oakden, so that the MEP could “avoid any accusation of bias”.

But it was revealed in March that Oakden contradicted Coburn in a subsequent email to party members which stated: “I will not be ranking candidates in Scotland, I am not picking the lists for Scottish regions, nor am I allocating candidates to regions.

“The NEC (National Executive Committee), who will ultimately decide the final lists have determined that the UKIP Leader in Scotland should devise a list, including candidate rankings for each region of Scotland.”

Coburn later denied that he was involved in the process and insisted he was “not imposing anyone on anyone”.

But an email from Crowther appears to confirm that Coburn did indeed choose who would stand where – and placed himself top of UKIP’s regional list in the Highlands and Islands.

One branch chair in Scotland, who asked not to be named, reached out to Crowther before Coburn’s choices were announced and said they would quit UKIP unless the NEC implemented the assessment team’s recommendations.

An email sent to Crowther on March 28 – which was copied to several members of the ruling executive committee, including former Tory MP Neil Hamilton – said: “I refuse to believe that the NEC would choose to give a candidate any control whatsoever over a candidate list. This must surely be a mistake.”

Crowther replied on the same day to say: “I'm afraid that is the situation. I hope you will stay with us and help plot the way forward after June 23rd.”

The branch chair’s subsequent reply to Crowther, which was copied to party leader Nigel Farage, said: “Thanks for your email. Candidate papers, as you know, have not be lodged. This is the window to turn the wheel, if the NEC is minded to. Are you and the NEC unable or unprepared to allow Scottish membership a credible process?”

Crowther did not reply, which prompted another branch chair to email the barbed comment: “Democracy? My ass. They have no interest in the membership up here or UKIP in Scotland, otherwise this would been sorted a long time ago.”

It is understood UKIP planned to field four candidates in each of Scotland’s eight regions but several hopefuls withdrew in the wake of the email exchange, leaving the party with three candidates in five regions and four in only three areas.

A UKIP Scotland source, who asked not to be named, said: “UKIP's clear contempt for the Scottish membership is why UKIP is haemorrhaging members. UKIP is plainly the wrong party for Scottish democrats.”

Another UKIP member said: “I was congratulated by Paul Oakden for getting through the selection for Holyrood and was on the NEC list, then dropped by Coburn and his cabal of fawning sycophants.

“I'm sad in a way that my life experience and skills are being disregarded in favour of less able people but if that's what UKIP thinks will get them elected then good luck to them. I won't be campaigning now and most definitely not voting for a rag bag bunch like them.”

A UKIP spokesman said: “The NEC decided to allow UKIP Scotland to finalise its regional lists, following an assessment process. We are satisfied that the candidates are excellent, and the right people to represent their constituents in the Scottish Parliament, including the huge number of Scots who do not wish to see the break-up of the United Kingdom or its loss of sovereignty to an unelected bureaucracy in Brussels.”