David Coburn, who will be introduced as the party's Euro hopeful at the launch in Glasgow today, was recently confirmed as a Westminster candidate 350 miles away in a London borough.
The event is also likely to be hamstrung by party rebels staging an alternative bash for Ukip members in Stirling.
The anti-European Union party has recorded electoral victories in England but enjoyed little success north of the Border.
Ukip desperately wants to return an MEP from Scotland in May's election, but a civil war is tearing the party to shreds.
Six of the nine shortlisted candidates in Ukip's internal selection withdrew before ballot papers were sent following a bout of infighting.
Ukip pushed ahead with the vote and the contest was won by Coburn, who until recently was the party's London chair.
His candidacy will be the focal point of Ukip's election launch this afternoon in the Grand Central Hotel in Glasgow.
However, Coburn is facing questions over his commitment to Scotland. It can be revealed that the Glasgow-educated businessman is also Ukip's Westminster candidate for Bexleyheath & Crayford in 2015.
The branch website confirmed his nomination, adding: "David stood for Bexley and Old Sidcup at the last election and vowed to stand in Bexley again. David has been Chairman of the Bexley Branch for four years and has built it into an effective fighting force which will be taking council seats in May with an exciting line-up of enthusiastic candidates."
With only a 12-month gap between the European and Westminster elections, and a term in Brussels lasting five years, Coburn's decision leaves open the possibility of him holding two positions.
In his pitch to Ukip Scotland members for the European election, he said getting elected to Brussels would be a stepping stone to Westminster.
Today's launch may be sparsely attended by Ukip Scotland members, who have been invited to a separate event 25 miles away.
Until recently, Lord Monckton was party leader north of the Border, while Mike Scott-Hayward and Peter Adams were respectively chair and regional organiser. All are deemed party moderates.
However, Monckton was fired recently, and Scott-Hayward and Adams resigned shortly after.
The trio have invited Ukip members to Stirling's Albert Halls to celebrate the party's 21st birthday. The "historic rally" is scheduled to start 90 minutes before the European launch.
According to the invitation, the event is billed as "Learning from yesterday, partying today, planning for tomorrow".
It starts with a "welcome" by Monckton, followed by Scott-Hayward talking about "the past year". Ex-chair Paul Henke is also due to speak, as is former fundraiser Malcolm Macaskill.
A Ukip source said: "The campaign launch in Glasgow is going to be a farce. Most of the folk with any credibility will be in Stirling, and it also looks like Coburn's ambitions are in London, not Scotland."
The source added that "hardliners" had taken over the party. Right-winger Misty Thackeray, who said Glasgow City Council was for "gays, catholics [and] communists", is currently interim chair.
Thackeray has also described Geert Wilders, the far-right leader of the Freedom Party in the Netherlands, as "great".
Councillor Maggie Chapman, the Scottish Greens' lead candidate for the European election, said: "Voters in Scotland will be insulted by an outfit that thinks it can parachute in a London Westminster candidate for an election here. It's increasingly clear they cannot be taken seriously.
"Ukip has no representation in Scotland and no interest in Scotland and is only being taken seriously as a result of a curious fascination for them elsewhere in the UK. A Scottish Green vote in May is what stands in the way of Ukip being elected in Scotland."
The Nationalist MEP Alyn Smith said: "It's always been clear that Ukip are totally irrelevant in Scotland. That they have admitted defeat in the European Parliament elections before the campaign has even begun shows that they know it too."
Coburn said: "I'll do what is best to get us out of the European Union."