Nigel Farage: "You have all the charisma of a damp rag"
The head of the European parliament has summoned British Eurosceptic MEP Nigel Farage over his tirade against European Council President Herman van Rompuy.
Parliament President Jerzy Buzek is expected to reprimand Mr Farage at the meeting on Tuesday.
Mr Farage, the leader of the UK Independence Party (UKIP) group in the parliament, could face a suspension.
Mr Farage drew jeers on Wednesday when he told the chamber Mr Van Rompuy had "the charisma of a damp rag".
He also said Mr Van Rompuy had the appearance of a "low-grade bank clerk".
The attack came as Mr Van Rompuy, a former Belgian prime minister, made his maiden appearance in parliament in Brussels.
Mr Buzek is said to consider Mr Farage's outburst to have been "completely undignified", believing it "crossed a line" between the right to free speech and being plain insulting.
Mr Farage's party, UKIP, campaigns for the withdrawal of Britain from the European Union. It has 13 representatives in the European parliament.
Possible penalties against Mr Farage range from a verbal reprimand to a 10-day suspension from parliament.
Mr Farage opened his attack against Mr Van Rompuy by saying "I don't want to be rude" - before launching into a personal attack lasting several minutes.
"Who are you? I'd never heard of you, nobody in Europe had ever heard of you," Mr Farage said.
"You seem to have a loathing for the very concept of the existence of nation states," he continued, adding: "Perhaps that's because you come from Belgium, which is pretty much a non-country."
Mr Farage, known for his outspoken interventions, did admit that he thought Mr Van Rompuy was "competent and capable", adding that this made him "dangerous".
"I have no doubt that your intention is to be the quiet assassin of European democracy and of European nation states," he said.
Mr Van Rompuy, 62, was chosen unanimously by the governments of the EU's 27 member states to take on the role of the first permanent European Council president.
Mr Van Rompuy said he held Mr Farage's comments "in contempt", without elaborating.