Diane James' spokesman has admitted to IBTimes UK that he apparently has no idea who is going to win Ukip's leadership election, on the eve of the 15 September announcement. "Our meetings have gone well across the country, there's no polling to speak of and it's a disparate electorate who are voting in the secrecy of their own homes so we have no feeling whatsoever really," the spinner said.

"I don't even have a hunch. Diane's done her best to put her case to the membership of Ukip."

But despite the spokesman's reservations, the bookmakers have the South East of England MEP as favourite to succeed Nigel Farage.

Ladbrokes, who are no longer taking bets, had James at 1/10 (90% chance), with Cambridgeshire councillor Lisa Duffy at 10/1, while William Hill has James at 1/5 favourite and Duffy at 9/2.

James, the deputy chair of Ukip, become favourite after Ukip's migration spokesman Steven Woolfe MEP failed to get on the ballot because he submitted his application late.

Pro-Farage supporters, including the Leave.EU group and co-founder Arron Banks, have since endorsed James. Her main competition has come from Duffy, who has the backing of Patrick O'Flynn MEP and Ukip heavyweight Suzanne Evans.

West Midlands MEP Bill Etheridge, Ukip National Executive Committee member Liz Jones and former pro-wrestler Philip Broughton are also in the running.

North East of England MEP Jonathan Arnott quit the race in August. The 35-year-old withdrew after admitting the best he could hope for would be second place. "There is no prize for a silver medal in a leadership contest," Arnott said.

James, meanwhile, has been criticised for her poor attendance record at election hustings and failing to provide new policies. "What I have put forward is what I've called my first 100 days programme," she told BBC Radio 4's programme in August.

Ukip returned one MP and secured more than 3.8 million votes and a 12.7% share of the vote at the general election, but, with Britain's decision to split from the EU, the future looks uncertain for the Eurosceptic party.