European Commission President Jean-Claude Juncker slammed UKIP leader Nigel Farage at the first European Parliament meeting since the Brexit vote on Tuesday, asking "why are you here?" and showing he will not be walked over when it comes to exit negotiations.
"To some extent I'm really surprised you are here," Juncker said to the outspoken Brexit leader, who campaigned on a platform of taking back border control and who yesterday apologised to New Zealanders for Britain turning its back on them when it joined the ECC.
"You were fighting for the exit ... why are you here?"
The comments came in an extraordinary session of the European Parliament to cap off an unprecedented few days in politics that saw the UK vote to leave the EU.
The shock result has opened a chasm of uncertainty about what happens next with Vote Leave leaders scrambling for an answer.
Meanwhile both the Conservative and Labour parties are searching for a new leader while Mr Farage is worried about "backsliding" from Conservative Brexiteers who may try to retain access to the single market.
While formal negotiations on the exit process must wait until the UK triggers Article 50 of the Lisbon Treaty which sets in motion a two-year process, the big unknown is the terms the European parliament will set which must be strong enough to deter others but gentle enough so as not to trigger further economic shocks.
Mr Juncker called for a Presidential ban on commissioners holding secret talks with UK leaders before the official exit process begins.
"They can have no preliminary discussions. No notification, no negotiation," he said on Tuesday during an explosive session of a normally dull parliament.
Hear Mike Hosking's interview with Nigel Farage here:
"We can't have secret attempts to take the British government aside to become informal secret negotiations ... that cannot happen. I've made a very clear command to all commissioners there can be no secret negotiations."
Juncker has previously described the decision to leave as not being an "amicable divorce" even though it was "not a tight love affair".
The harsh words didn't end there with former Belgian Prime Minister Guy Verhofstadt blasting Farage for "lying" during the campaign about Turkey's accession process to the EU and for a poster proclaiming the country was at "breaking point".
"It's that climate of fear that has been created, of negativism that has been created - that is the most shocking thing that has happened in Britain - not the choice of the people, because the choice of the people is democracy."
He also slammed the "selfishness" of Boris Johnson for backing the Leave camp out of a sense of personal ambition.
"It is an act against the bickering of the Tory leadership and against the selfishness of one man (Mr Johnson) who was ready to do anything, even to sacrifice the voice of 70 million British citizens to become Prime Minister of the UK - or should I say Prime Minister of the dual kingdom of England and Wales," he said.
The final insult was reserved for Farage: "Finally we will be getting rid of the biggest waste in the EU budget - that we have paid for 17 years of your salary."
Undeterred, the UKIP leader jeered back "you're not laughing now" at the European leaders and called for a tariff-free zone between Britain and Europe.
Mr Farage insulted them by saying "virtually none of you have ever done in a proper job in your lives" and said they were angry because they are "in denial" about EU failings.
"The biggest problem you've got and the main reason the UK voted the way it did is you have by stealth, by deception ... you have imposed upon them a political union."
It comes as German Chancellor Angela Merkel warned the UK it will not be able to "cherry pick" terms of membership from outside the bloc.
"We will ensure there are no negotiations based on the principle of cherrypicking," she said.
"There must be and will be a noticeable difference between whether a country wants to be a member of the European Union family or not."
"Anyone wishing to leave this family cannot expect to lose all the obligations but keep the privileges."
How the negotiation process will work is one of hundreds of questions that have emerged from the vote which is also subject to debate from UK political leaders.
Prime Minster David Cameron is at pains to ensure that nothing will change until the type of relationship the UK wants to have has been established. Only then will the UK invoke Article 50, marking the start of negotiations.
Mr Cameron will meet with European leaders in Brussels on Tuesday evening.