Nigel Farage told fellow MEPs “you’re not laughing now” as he was barracked and booed at an emergency meeting of the European Parliament to discuss Brexit.
The Ukip leader accused them of being “in denial” about the euro crisis, immigration and the imposition “by stealth, by deception, without ever telling the truth” of a political union.
Offering a tongue in cheek “thank you for the warm welcome”, he told them: “When I came here 17 years ago and said I wanted to lead a campaign to get Britain to leave the European Union you all laughed at me.
“Well I have to say you’re not laughing now are you?”
As the session was disrupted by constant shouts of dissent, Parliament president Martin Schulz was forced to intervene, warning members that “one major quality of democracy is that you listen to those even if you don’t share their opinion”.
At a highly charged session in the Brussels chamber, Mr Farage declared: “The reason you are so upset, the reason you are so angry, has been perfectly clear from all the angry exchanges this morning: you are in denial.
“You are in denial that your currency is failing,” he said.
Facing down more boos, he said: “As a policy to impose poverty on Greece and the rest of the Mediterranean, you have done very well.
“You are in denial over (German chancellor) Mrs Merkel’s call last year for as many people as possible to cross the Mediterranean into the European Union, which has led to massive divisions between countries and within countries.
“But the biggest problem you have got, and the main reason the United Kingdom voted the way it did, is that you have, by stealth, by deception, without ever telling the truth to the British or the rest of the peoples of Europe, you have imposed upon them a political union.”
Earlier Mr Farage sparred with EU Commission president Jean-Claude Juncker, who questioned why he had attended.
“That’s the last time you are applauding here,” Mr Juncker said after the fiercely anti-EU politician applauded his opening statement that Europe “must respect British democracy and the way it has expressed its view”.
“To some extent I am really surprised that you are here,” he told him.
“You were fighting for the exit, the British people voted in favour of the exit. Why are you here?”
Mr Farage told him it was a “pleasure”.
The pair were seen to share an embrace, with the famously tactile Mr Juncker appearing to kiss the politician on the ear.