Suzanne Evans has announced she is standing to be leader of Ukip - and vowed to make the party less "toxic".
Evans warned Ukip risked being turned into a Donald Trump-style party by Nigel Farage and his allies, but dismissed this strategy, insisting there is no groundswell of support for "far-right" polices in the UK.
Her announcement comes after Arron Banks, the party's most high-profile donor and former aide to Farage, announced he is backing Raheem Kassam for the leadership.
Evans told the BBC's Andrew Marr Show: "Our future as a political party in Britain does not lie in that far-right wing. I don't see a groundswell of opinion in this country for more far-right wing policies.
"I don't see a groundswell of opinion for the right to bear arms in America."
Evans said she "absolutely" thought Kassam will take Ukip in a far-right direction but "our members don't want that".
She said: "We've taken a lot of stick in Ukip because perhaps we have had a slightly more toxic image than we should have had.
"And our members, the ones that are doing the campaigning, have felt the brunt of that - being abused, being physically and verbally assaulted on the streets.
"They don't want to have a fresh injection of toxicity that's going to make it even more difficult for them, they want policies that help us win."
Farage has been a vocal proponent of Trump and has appeared at a rally for the controversial presidential candidate.
Evans, who wrote her party's 2015 manifesto but has since fallen out with Farage, was unable to stand in the last leadership election after being suspended from the party for disloyalty.
But she tried to brush off claims that her unpopularity with the Ukip leader and his close ally Banks would harm her chances of being elected to lead the party.
She said there has been "too much testosterone" in Ukip and it is ripe for change.
Evans said: "I don't know if he'll (Farage) back me or not, and that's actually not important because we are going into a new direction now."
The leadership hopeful said she has "more than enough signatures" on her nomination form already, and dismissed claims the party's finances are in a perilous state.
She said: "I have been 100% assured that actually we are not doing nearly as badly as the headlines suggest, and indeed Arron Banks is by no means our major donor. If he walked tomorrow Ukip could survive perfectly well without him."
She said the party needs to occupy the common-sense centre ground.
Making her pitch for leader, she told the show: "I think I'm the right person to lead Ukip into the challenges ahead, to be able to beat the first past the post system that we have at the moment by broadening our appeal and getting MPs into Westminster.
"But first and foremost I think I am absolutely the right person to champion the cause of those 17.4 million people who voted to leave the European Union and are now seeing their democratic choice being undermined by the political class."
She said politicians, activists and lawyers are "trying to undermine the will of the people" and she will stand up to them.
"I will be there breathing down their necks to make sure that we have that tug of war - they are trying to pull us back to Brussels, I'm going to grab hold of the other end of the rope and make sure we pull us out to the EU exit door", she said.
Kassam hit back at the comments, saying: "It is sad that 60 seconds after she launched her campaign on the BBC, Suzanne Evans attacked me and my thousands of supporters as 'far right'. This is a project fear tactic and Ukipers are sick of these smears.
"But we're going to rise above it. When she goes low, we go high, to quote Michelle Obama.
"I invite Suzanne Evans to meet with me at her earliest convenience to discuss her concerns, and how I think this party should be uniting to fight for Brexit, border control and more, and not attacking one another."