Allegations are latest in string of reports based on recordings secretly made at Warsaw restaurant. Poland has ordered an investigation into claims by a magazine that a senior adviser to European Council president Donald Tusk influenced the removal of a critical newspaper editor during Mr Tusk’s term as Polish prime minister.

Do Rzeczy, a rightwing weekly, reported on Monday that in April 2014, Pawel Gras, then a minister in Mr Tusk’s cabinet, complained to Jan Kulczyk, then Poland’s richest man, about negative coverage of Mr Tusk and his family in the Fakt tabloid newspaper.

The magazine had obtained a leak which it says details how Mr Kulczyk, who died last year, offered to raise the issue with Friede Springer, widow of media magnate Axel Springer, whose company owns the newspaper. Six weeks later, the editor left the publication.

In a statement, Axel Springer Poland said it “would not discuss this conspiracy theory, which is totally absurd”, and said any allegations that political pressure affected leadership decisions were “untrue”.

Mrs Springer could not be reached for comment.

A spokesman for Mr Tusk in Brussels said the European Council president had no comment on the revelations.

Mr Gras now serves as senior political and communication adviser to Mr Tusk in Brussels.

The allegations are the latest in a string of media reports based on recordings reportedly secretly made at a high-end restaurant in Warsaw popular with senior politicians in 2014.

It was not clear how the magazine obtained the recordings, which the Financial Times has not been able to verify.

Polish prime minister Beata Szydlo, whose Law and Justice party defeated Mr Tusk’s Civic Platform party in the October general election, said on Monday that she had asked her justice minister to investigate the claims.

“If the information from the article gets confirmed, it is really a thing which is beyond any kind of comment. We cannot imagine that in the democratic state of rule of law these kind of things can happen,” Ms Szydlo said.

The investigation is likely to strain relations between Warsaw and Mr Tusk’s office. It comes a few months after Poland agreed to push ahead with the prosecution of a former aide to Mr Tusk over the 2010 Smolensk air crash that killed Lech Kaczynski, who was president at the time.

Previous reports of recordings allegedly made of senior Polish government officials and businessmen led to the resignation of six ministers and the s parliament Speaker last June.