Ukip's most high-profile donor has backed a former aide to Nigel Farage for the party leadership amid speculation ex-deputy leader Paul Nuttall was poised to enter the race.
Insurance tycoon Arron Banks said he was backing Raheem Kassam for the leadership "despite Paul Nuttall running" for the job.
Mr Nuttall has yet to publicly declare if he will stand in the contest, having declined to stand in the previous leadership race earlier this year.
The present leadership contest was triggered when Diane James quit after just 18 days in charge and has been thrown wide open after frontrunner Steven Woolfe quit in the wake of an altercation with a fellow MEP.
Mr Kassam, an ex-chief of staff to Mr Farage, welcomed the support offered by Mr Banks, the co-founder of the Leave.EU Brexit campaign.
He said: "This is a major endorsement from someone who has been one of the driving forces behind Ukip in recent years.
"Mr Banks ploughed his personal time and money into the referendum campaign and the party, and for those wondering whether he still stood with Ukip, this is a very clear sign: he does, under a Kassam leadership.
"I'd like to thank Arron for the brave and important support, and I look forward to working with him to make Ukip great again."
Mr Banks said on Twitter: "I've been very impressed with Raheem's ideas, despite Paul Nuttall running I think he's the candidate to beat. He's got my support."
The new Ukip leader will be announced on November 28, with nominations to replace Ms James closing on October 31.
Another potential leadership contender, former deputy chairman Suzanne Evans, is listed to appear on the BBC's Andrew Marr Show on Sunday, fuelling speculation she will enter the race.