The family of the man whose story inspired the Academy Award-winning film ‘The Pianist’ has won a long-running defamation suit over claims that he was a Nazi collaborator.

Polish-Jewish Wladyslaw Szpilman’s story of how his music helped him to survive the Holocaust was made into a film in 2002 by Roman Polanski.

In 2013, Szpilman’s widow and son filed a suit against Agata Tuszynska, the author and publisher of a biography of Polish singer Wiera Gran, in which Gran - who has also been accused of cooperating with the Nazis - claimed that Szpilman had worked for the Nazis in the Warsaw Ghetto.

The Szpilmans announced on Monday that the Warsaw Court of Appeals had overturned the original ruling that the book was protected under free speech. Tuszynska now has 15 days to publicly apologise and to remove the references from future editions of the book.

“This ruling will allow the ethical standards in Poland to improve and bring into question the poorly interpreted notion of freedom of speech,” said Szpilman’s son, Andrzej.