Warsaw  - Poland's iconic former trade union leader and ex- president Lech Walesa again defended himself Tuesday against accusations that he worked for the communist-era secret police (SB).

"I have never been a secret police agent," Walesa said during an interview with Polskie Radio.

Walesa defeated the secret police, not the other way round, the 64-year-old said.

As early as December 1970, Walesa took part in protests against Poland's communist regime when he was working at the Lenin docks in the Baltic port of Gdansk.

In 1980, he founded Poland's first free trade union, Solidarnosc, and 10 years later, after the communist regime was ousted, he was elected as the first president of the newly democratic Poland.

In 1983 he was awarded the Nobel Peace Prize.

Poland's Institute of National Remembrance (IPN) is planning to publish a book about Walesa.

According to Polish media reports, the book's authors are believed to have uncovered documents which indicate contact between the trade union hero and the secret services in the 1970s.

The documents are supposed to show that Walesa was employed as an unofficial operative for the secret police under the alias Bolek.

The IPN authors also claim that Walesa attempted to cover up his past when he was president, a move that is against the constitution.

Rumours that Walesa worked as a secret service agent have been circulated by his opponents since Poland adopted democracy.

Walesa has called the book a "scandal" and has pledged to reveal who Bolek is after the book is published.

Once he had done that, the IPN would have to destroy the complete print run of the book, Walesa said. (dpa)