Peter Whittle has become the "massive" favourite to succeed Paul Nuttall after Nigel Farage ruled out another Ukip leadership bid, it emerged on Monday 3 July.
A party source told IBTimes UK that Whittle's media exposure, as deputy leader of Ukip and group leader of Ukip's two-strong London Assembly group, means that he has a big advantage over his rivals.
"Whittle is a massive favourite at the moment because he's the only [candidate] people know," said the source, who is currently not backing a candidate. "Most of our members might not be on Twitter and most of them don't go to local branch meetings."
The comments come just a day after Farage said would it would be "premature" for him to return to the frontline of British politics.
"But I'm still committed to the great Brexit battle and I will continue in my role as the leader of a group in the European Parliament, overseeing the Brexit process," he told The Sunday Telegraph.
The decision confirmed what a senior Ukip source told IBTimes UK in July – that the odds of Farage running were "slim".
The Eurosceptic firebrand has become a media commentator for Fox News and LBC Radio since his decision to quit the top of Ukip in the wake of the Brexit vote last year. Ukip, meanwhile, have slipped to as low as 2% in the opinion polls after winning just under 600,000 votes at the general election, down from 3.8 million votes in 2015.
Whittle, a Farage ally, dropped out of the second Ukip leadership contest in 2016 and endorsed Nuttall, who easily beat then former deputy party chair Suzanne Evans and John Rees-Evans (62.6%, 19.6% and 18.1%, respectively).
Whittle, a former TV producer, told IBTimes UK in March that his party had a "bright future" and pointed to cultural issues he wanted Ukip to concentrate on.
"Most political parties are set up for one purpose or another and they go on," he said.
"And so we will be talking about immigration, we will be talking about threat from radical Islam and we will be talking about foreign aid."
Rees-Evans, who has a large social media following, with more than 70,000 followers on Twitter and 4,000 likes on Facebook, is currently considering whether to make another leadership bid.
"For those asking, over the next week I shall be reflecting very, very seriously about Ukip's future, and I expect to share my conclusions the following week," he said in a statement.
"While one cannot refute Nigel's criticisms [of the party's inner-workings], it is nonetheless absolutely clear that Britain needs a party like Ukip more now than ever before; a party willing to fight incessantly and inexorably for genuine independence for the people of Britain, from all forms of undemocratic domination and usurpation of power, whether this be foreign or domestic."
Elsewhere, anti-Islam campaigner Anne Marie Waters has announced her intention to run for the top Ukip job. But Walters, who runs that Sharia Watch website and has called Islam "evil", has been blocked from running in the 2016 London Assembly elections and deselected as a general election candidate in 2017.
Ukip's ruling body, the 15-strong National Executive Committee, will decide if the potential candidates, including Bill Etheridge MEP, are able to go through to the next round of the contest.
A party spokesman said nominations will close on 28 July, with a final list of candidates being published on 18 August and the new leader announced at Ukip's annual conference on 29 September. Whittle is 2/1 favourite, with Waters at 4/1 and Etheridge at 7/1, according to bookmakers Ladbrokes.