The hot favourite to succeed Nigel Farage will find out on Tuesday whether his campaign has fallen at the first hurdle after he missed a deadline to submit his nomination to battle in the party's leadership contest by almost 20 minutes.
Candidates were required their application alongside 50 nominations and a cheque for £5,000 to the party by midday today.
Ukip's migration and financial affairs spokesman Steven Woolfe was the 1/4 favourite to win the leadership contest, but missed the deadline, putting his bid to head the party in doubt.
A party vetting committee will meet on Tuesday at noon to approve the full list of candidates for the ballot, and decide whether Woolfe will make the list.
A spokesman for Woolfe has blamed technical issues for the delay, but added that the MEP is confident that he remains in the race.
"[Woolfe] submitted his application form at 11.35 this morning in advance of the midday deadline. However, due to technical problems on the party system, it did not successfully go through until 12.17pm," they said.
"Mr Woolfe was speaking to party officials responsible for handling the application process throughout this time and right up to the deadline. He informed them that he was having technical problems. these problems were finally resolved and the paperwork submitted."
According to Ladbrokes, Ukip deputy chairman and South East England MEP Diane James was 5/1 second favourite to succeed Farage before news of Woolfe's nomination problems emerged.