Lord Heseltine has accused Ukip of being a "racist" party, comparing their campaigning to Enoch Powell.
The Tory grandee also likened Nigel Farage's party to that of Marine Le Pen in France, saying: "You always have these right-wing, racist operations, pandering to the lowest common denominator of politics, and that's what's happening."
Appearing on the BBC's Daily Politics on Wednesday, he said he was not accusing Farage himself, but said "everyone knows" there was a racist agenda, pointing to the party's members.
Presenter Andrew Neil asked him: "Are you saying Ukip is racist?"
Heseltine replied: "Of course it's racist, of course.
"Who doubts that? That language, the membership, the rhetoric, who doubts it?"
Neil asked whether he was saying Farage was racist.
Heseltine replied: "I didn't say he is. His party is very attractive to a racist agenda and everyone knows that.
"Let's not pretend there's not an agenda for that."
Comparing Ukip to right-wing former Tory MP Enoch Powell, he added: "That agenda is there in every society, all the time.
"At your peril do you take it up."
HuffPost UK has asked Ukip to respond to Heseltine's comments.
The party has battled racism accusations in recent months, with extreme views expressed by local candidates and claims that Farage was labelled a fascist at school.
The euroscpetics hope to be the largest party after next year's European elections and has its sights set on winning a first Parliamentary seat in 2015.