Rishi Sunak was told he is the “quinoa salad” to Nigel Farage’s “Sunday roast” during a BBC interview.
The prime minister clashed with veteran presenter Nick Robinson on Monday evening.
Reform UK, the populist party now led by Farage, poses a serious threat from the right to the Conservatives at the election on July 4.
Robinson told Sunak: “The problem with that is that Nigel Farage has destroyed David Cameron’s premiership. He helped bring down Theresa May and he’s now coming for you.
“Isn’t your problem that many Conservatives think he’s more of a Conservative than you are?”
The BBC interviewer added: “You see, a lot of people looking at him and you, they think these Conservatives, he’s a kind of Sunday roast with all the trimmings and you’re a quinoa salad.”
Sunak hit back, warning voters who were tempted to back Reform would make it “more likely” that Labour won.
“I think the policies are what matter. The substance is what matters, Nick,” the prime minister added.
“The choice for everybody, there’s only going to be one of two people who’s prime minister, Keir Starmer or myself.”
It came after Reform defended one of its candidates who said Britain should have done a deal with Adolf Hitler to avoid involvement in the Second World War.
During the 30-minute interview, Suank was challenged over NHS waiting lists, immigration, home ownership and “bunking off” the D-Day ceremony.