Italian junior culture minister and art critic Vittorio Sgarbi, under investigation over possession of a stolen painting, said on Friday he was quitting because Rome's antitrust body was trying to curb his unofficial duties.
Sgarbi, 71, is a long-serving parliamentarian and outspoken TV personality.
Sgarbi has been under pressure to resign for weeks over the painting scandal, but said he was quitting "to avoid a conflict of interest" before beginning a lecture on Renaissance artist Michelangelo in Milan, Reuters reported.
Sgarbi said the antitrust authority, which is investigating him over a possible conflict of interest, had informed him he should not attend an art conference.
He told his audience he had decided to preserve his freedom rather than respect its instructions.
"According to the antitrust notice, I should not talk about art, I should not deal with art. I should be a junior minister dealing with administrative duties, and limited ones," he said.
He attacked Culture Minister Gennaro Sangiuliano for not backing him over what Sgarbi said were "anonymous letters" to the ministry alleging he was accepting payments for non-ministerial duties, in a breach of regulations.
Prosecutors are investigating the politician, whose brief includes protecting the country's cultural heritage, over his ownership of a 17th century painting that police say was stolen from a castle near Turin in 2013. He denies all wrongdoing.