Tusk has 'overwhelming majority' among EU leaders

She claimed Tusk had showed “clear support” for the Polish opposition's attempt to block the work of the Polish parliament.

“Under the Polish constitutional circumstances, the attempt to block the adoption of the budget was an attempt to overthrow the government by means of non-parliamentary methods,” Szydlo’s letter said.

Tusk was prime minister of Poland for centre-right Civic Platform party before becoming European Council chief.

He is the archenemy of Jaroslaw Kaczynski, the head of Poland’s ruling Law and Justice (PiS) party, who has accused Tusk of plotting with Russia to kill his twin brother in the 2010 air disaster in Smolensk.

Kaczynski holds a new grudge against Tusk for urging the Polish government to respect its constitution in a dispute between Warsaw and the European Commission over the rule of law.

The Council chief irked the PiS head still further by announcing in Malta last month that he wanted a second EU term without first asking for Warsaw’s blessing.

EU diplomats said Poland would be unable to stop Tusk’s reappointment due to his wide respect in Europe.

They said Poland would also be unlikely to get a special EU summit on the reappointment controversy.

In another blow, Maltese prime minister Joseph Muscat, whose country holds the EU presidency, said he would not invite Kaczynski’s candidate, Polish MEP Jacek Saryusz-Wolski, to Thursday’s summit despite Warsaw’s request.

Warsaw had hoped that given more time, more capitals could be convinced to support Saryusz-Wolski, who defected from the Civic Platform to seek the EU post.

Szydlo travelled to Brussels on Wednesday ahead of the summit to say Tusk should not get back in unless he had “broad support”.

But EU diplomats said in Brussels also on Wednesday that there was a "clear overwhelming majority" for Tusk.

Hungary and the UK said that they were happy with Tusk’s work, but did commit publicly to supporting the incumbent.

Some EU officials said that Poland’s “stubbornness” not only hurt Poland politically, but the entire central European region, of which Tusk stands as a symbol.

Others said that inability to name the next Council president could have “devastating consequences” for EU credibility at a time when European citizens expect results instead of infighting.

Muscat, who will chair the meeting during this session instead of Tusk, has a crucial role in keeping the atmosphere constructive and the discussion short, diplomats said.

If Muscat concludes there is enough support for Tusk, he does not need to call for a vote, and the session could end quickly, depending on how much resistance Poland puts up.

Tusk himself said on Wednesday in Brussels that he was not responsible for the political clash and that he has been and will be "impartial and politically neutral" as president.

"I am also responsible to protect EU values and principles, that's my role and deep belief," he said.