Suzanne Evans and Paul Nuttall bid for Ukip leadership
Suzanne Evans and Paul Nuttall have both announced they are standing to be leader of crisis-hit Ukip.
The two politicians both promised to hold the Government's feet to the fire on Brexit if they are elected to the helm of the party.
But while Mr Nuttall struck a conciliatory tone and pitched himself as the "unity" candidate, Ms Evans used her bid to launch a scathing attack on the current leadership.
She said Ukip needs to shed its "toxic" image and warned it risks becoming a Donald Trump-style party under the leadership of Nigel Farage and his allies.
She accused her leadership rival Raheem Kassam of being a "far-right" candidate that will take Ukip in the wrong direction.
Ms 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."
Ms Evans said she "absolutely" thought Mr Kassam - who has won the backing of party donor Arron Banks - 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."
Mr Farage is close to Mr Trump, appearing at a rally in the US for the controversial presidential candidate.
Ms Evans, who wrote her party's 2015 manifesto but has since fallen out with Mr 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 Mr Banks would harm her chances of being elected to lead the party.
Mr Farage hit out at Ms Evans' remarks, telling ITV's Peston on Sunday: "For her to talk about the party being toxic, for her to already declare one of the candidates who is running, Raheem Kassam, as being far-right, I don't view this as being a very good start."
While Mr Kassam accused Ms Evans of a "project fear tactic" and "smears".
Ukip has been plunged into turmoil since Diane James quit as leader after just 18 days in the job.
Steven Woolfe, the frontrunner to replace her, also left the party in the wake of an altercation with another party member after which he ended up in hospital.
Throwing his hat in the ring, Mr Nuttall, Ukip North West MEP, said the party faced an "existential crisis" and could disappear unless it unified.
He told the BBC's Sunday Politics: "I've made the decision that I'll put my name forward to be the next leader of Ukip.
"I have huge support out there across the country, not only among people at the top of the party in Westminster and with the MPs, but also among the grassroots.
"And I want to stand on the platform of being the unity candidate - Ukip needs to come together. I'm not going to be on here and gild the lily, Ukip at the moment is looking over the edge of a political cliff, it'll either step off or it will step back.
"And I want I be the candidate that will tell us to come back."
He said Ukip is facing an "existential crisis" and said he can be the "go-to man" to bring the party together.
"I want to ensure that Ukip is on the pitch to kick the ball into the open net that we have in British politics", he said.
He said the party needs to move on from its internal squabbling and unify behind the new leader.
Mr Kassam said he was not "far right" and was "disappointed" with Ms Evans' attack on him.
"When she does things like this, it really undermines her, it undermines her campaign and it is an attack on a lot of the party members," he said.
He told Sky News' Murnaghan programme that he would "continue Nigel Farage's legacy inside Ukip", but added that he wanted to talk to the rival factions in the party.
"I think now, especially after that incident with Steven Woolfe in the European Parliament, we have to say 'this has gone too far'. We are all in the same party and if we wish to remain in the same party let's sit down around the table together."
Mr Kassam insisted that his plan to end the blanket ban on former members of far-right groups joining Ukip would not see ex-English Defence League leader Tommy Robinson sign up.
The Ukip leadership candidate said he had spoken at a rally held by Pegida UK, a group established by Mr Robinson, but he said: "Tommy Robinson would not have a place in Ukip. I believe he has even said that himself."
Mr Kassam added: "How many members of the far-right are going to join a party led by a chap called Raheem Kassam?"