Health Secretary Jeremy Hunt urged Nigel Farage to condemn the latest controversial comments from one of his candidates, who suggested comedian Lenny Henry should emigrate to a "black country".
Mr Hunt pointed out that the remarks joined a list of other questionable interventions, including Ukip poster-boy Andre Lampitt arguing on Twitter that Islam is "evil" and Ed Miliband is not British. The party has also come under fire for an ad campaign warning of the dangers of immigration.
However, a YouGov poll for the Sunday Times indicates that Mr Farage is not sustaining significant damage from the furores, or persistent questions about his MEP expenses.
The firm gave Ukip an outright advantage for the first time, with 31% support compared to 28% for Labour, and the Tories languishing in third on 19%.
The results are in line with a ComRes poll for the Sunday Mirror and Independent on Sunday which put Ukip on 30%, Labour on 28%, and David Cameron's party on 21%.
Responding to a speech by Henry in which he complained that ethnic minorities were under-represented on British television, Ukip council candidate William Henwood tweeted: "He should emigrate to a black country. He does not have to live with whites."
Defending the words, he told the BBC: "I think if black people come to this country and don't like mixing with white people why are they here? If he wants a lot of blacks around go and live in a black country."
But Mr Hunt told Pienaar's Politics on BBC Radio 5 Live the comments were racist and "disgusting".