Newly-publicised documents have revived claims Lech Walesa, the giant of Poland´s struggle to overthrow communism, was a secret police informant in the 1970s - allegations still fuelling an old feud among postcommunist leaders.
Poland´s ruling conservatives, led by Jaroslaw Kaczynski, have leapt at the opportunity to question Walesa´s independence from the communist-era police after he became Poland´s first democratically elected president between 1990 and 1995.
His defenders say that whatever the authenticity of the documents, they do little to undermine the record of a man who was awarded the Nobel Peace Prize in 1983.
Walesa, 72, has said a batch of files found last week at the house of a late communist interior minister was fabricated, and denied he ever spied on fellow dissidents, an accusation he has faced repeatedly over two decades.
The new files contain a handwritten document signed "Lech Walesa" which includes a pledge to cooperate with the secret service. It mentions the codename "Bolek", long ascribed by critics to Walesa.
Other documents include typed descriptions of conversations with Bolek in which he describes the mood among workers in the Gdansk shipyard where Walesa was working at the time and where the Solidarity movement originated. There are invoices, apparently signed by "Bolek" for cash received in return for information.
Scans of the files have been published in the Polish press.
Some of the documents appear to have been written by secret police officials and some by Walesa.
Poland´s Institute of National Remembrance (IPN), a state agency tasked with investigating crimes "against the Polish Nation" from World War II until the collapse of communism, has said the documents in its possession are authentic, meaning they did originate from the secret service.
Forensic testing of the documents, including of handwriting purported to be Walesa´s, is under way.
Walesa´s critics argue the files put into question not only Walesa´s standing as a hero of the effort to end communist rule but also raise doubts about whether the country ever succeeded in fully shaking off the influence of pre-1989 communist officials.
"The Walesa legend probably cannot be defended any more," Foreign Minister Witold Waszczykowski told public television.
"We need to ask historians whether these issues linked to Lech Walesa and maybe others ...may have served as obstacles in the 1990s in terms of taking important decisions about state security."
Antoni Macierewicz, defence minister, went further, saying the files proved that post-communist Poland was a product of the secret police and not of democratically-elected institutions.
