Thun und Hohenstein is also Polish, a member of the centre-right European People's Party, and hails from the Civic Platform, which is in opposition in Poland.

Czarnecki used the phrase in a post on his website on 4 January, and in an interview a day later refused to apologise.

Six days later, four MEPs wrote a letter to European Parliament president Antonio Tajani, asking him to "firmly denounce [the] unacceptable and degrading statement".

"These remarks exceed the boundaries of responsible political discourse, both on a personal and on an institutional level," they wrote.

The letter was signed by the group leaders of the European People's Party (Manfred Weber), the Socialist and Democrats (Gianni Pittella), the Liberals (Guy Verhofstadt), and Greens (Philippe Lamberts).

They asked Tajani to "take appropriate action so that this deplorable behaviour cannot be connected with the European Parliament".

On Friday (12 January), EPP spokesman Pedro Lopez de Pablo told EUobserver at a press conference in Brussels that Czarnecki should no longer be allowed to be a vice-president of the European Parliament.

"MEPs who have an institutional role should not do politics insulting his colleagues," said Lopez de Pablo.

"We do feel that he no longer represents the European Parliament. He can continue being an MEP and doing the politics the way he does, which is insulting his colleagues, but he cannot represent anymore the house," he added.

Orwellian over-reaction?

Gareth Goldsmith, spokesman for Czarnecki's ECR group, responded by saying "political point-scoring" could be one of the motives for the move to strip Czarnecki of his vice-presidency title.

"It has just become a bit of a ... 'Orwellian'-type obsession with controlling language and controlling what people are saying," said Goldsmith.

"We have to be a little bit careful of what kind of territory we stride into," he added.

The European Parliament has fourteen vice-presidents, elected by MEPs. They can represent the parliament at ceremonies, and regularly preside over plenary sessions if Tajani is not available.

Vice-presidents are also part of an internal parliamentary body called the Bureau, which decides on all kinds of procedural issues.

The leaders of the political groups will meet next Thursday (18 January) to discuss the issue.

If leaders representing 60 percent of the seats in parliament, and at least three political groups, support the 'impeachment' procedure, it will be put to a vote in front of the whole plenary.

The four groups whose leaders signed the letter already represent 529 seats, or 70 percent.

A plenary vote on Czarnecki's position as vice-president will likely take place in the February session at the earliest.

MEPs will then have to decide if Czarnecki has been "guilty of serious misconduct", and vote to oust him with a majority of 66 percent – and a minimum of 376 votes.

Both EU parliament spokeswoman Marjory van den Broeke and EPP spokesman Lopez de Pablo said that this would be the first time the impeachment rule is triggered in the parliament.

"To my knowledge, yes. And I've been here a long, long time," said Van den Broeke.

The issue come amidst tensions between Poland and the EU institutions, in particular the European Commission, over the rule of law and what many believe to be the ruling PiS party's attempt to eradicate the independence of the judiciary.

An unprecedented move to trigger Article 7 of the EU treaty against Poland is underway, which could ultimately see Poland lose its EU voting rights - although not be expelled from the bloc.