A Ukip council candidate who said comedian Lenny Henry should leave Britain to live in a “black country” has resigned from the party.
William Henwood, who was hoping to represent Ukip in Enfield, made the comments in response to the comedian's claims that there were not enough ethnic minority faces on the BBC.
The Ukip candidate tweeted in response: “He should emigrate to a black country. He does not have to live with whites.”
A Ukip spokesman said Mr Henwood had resigned his membership of Ukip after it was "mutually agreed this would be the best course".
A Ukip spokesman said: "Mr Henwood's remarks about Lenny Henry caused enormous offence and Ukip MEP candidate for the West Midlands Bill Etheridge spoke for many in the party with his strong condemnation."
The party has also begun action to expel two members after an internal investigation found evidence of links to far-right groups.
One of the men was discovered to have been a member of the British National Party from 2005-2010, the second to have been a donor to the English Defence League.
The process to throw out the the two men, who have not been named, came as party leader Nigel Farage claimed attempts to portray Ukip as racist will prove a "disastrous mistake" for the established political parties.
Mr Farage was accused of aping far-right tactics and attracting extremists to his cause ahead of the May 22 European elections.
A series of controversies over offensive comments made by candidates and supporters and a stark anti-EU immigration poster campaign have failed to dent Ukip's soaring poll ratings which have put it on course to top the national poll.
And Mr Farage likened attempts to portray his party as racist with then prime minister Gordon Brown's dismissal of a voter who complained to him about the impact of immigration during the 2010 general election campaign as a "bigot".
"I think the British public will take this extremely badly. I believe they want and appreciate the new choices being offered to them by Ukip on issues like immigration control, and will certainly not appreciate being branded racist for doing so."
As well as the furore around Mr Henwood, would-be councillor Andre Lampitt was suspended hours after featuring in an election broadcast for expressing "repellent" racist and anti-Islamic views on social media.
Labour former minister Barbara Roche - who chairs the Migration Matters Trust with a Tory MP and Liberal Democrat peer - said the party was guilty of "a form of 'Euracism'".
"They are deploying the same language and tactics used by openly racist parties like the BNP, but instead of targeting migrants from Africa and Asia they are targeting migrants from within the EU," she said.
"It is no less offensive to say British families should be wary of Romanians moving in next door than it is to say it of Nigerians or Indians," she said, in response to Mr Farage's own warnings about the dangers posed by Eastern European immigrants.
Dismissing Mr Farage's claims that those exposed were "a few rotten apples", she said: "Andre Lampitt and William Henwood haven't stumbled into supporting Ukip by accident. They see a direct correlation between their own extremist views and those of the party they have been campaigning for."
Mr Farage issued an angry retort, however, as he continued to campaign around the country with his party riding high in the opinion polls and increasingly confident of achieving the political "earthquake" he has been promising for some time.
"I am really sorry that millions of people who have decided to vote Ukip next month now find themselves accused by the political establishment of supporting racism," he said.
"This is like the incident between Gordon Brown and Gillian Duffy at the last general election writ large: this time it is not merely one person being slandered by one establishment party, but huge numbers of decent British people under attack, and all three Westminster parties levelling the charge of racism and bigotry."
Ukip was now "recognised as a threat to the entire establishment" and the three main parties were ganging up and "slinging mud".
"They are trying to browbeat the British public into abandoning Ukip and sticking with open-door immigration by using the most disgraceful slurs.
This is the classic tactic of any cartel whose position is threatened by a new competitor in the market place.
"The electorate is not in the mood to be intimidated by the political establishment and Messrs Cameron, Miliband and Clegg have just made another disastrous mistake. I call on all fair-minded British people to swing behind Ukip and teach these creeps a lesson they won't forget in a hurry."