The decision to virtually make Dutta, who has been taking pot shots at the party leadership for months, a lameduck mayor was taken at a meeting chaired by Urban Development Minister Firhad Hakim in the presence of a majority of corporation councillors.
Dutta, a local legislator, however, seemed unperturbed, and invited BJP leader Mukul Roy for dinner at a posh club.
Asked whether it does not constitute breach of discipline, Dutta said: "Mukul Roy has come to give me his advice as he thinks I am in a bit of a problem. But I am yet to get any letter or call from the party about any such decision."
Roy said Dutta had helped the BJP in the just concluded Lok Sabha polls, but gave an evasive reply to a poser as to whether the mayor would join the saffron outfit.
"He has to take a decision first, and tell us about his intention. Then we will decide," said Roy.
Dutta, on his part, said that he continues to be the mayor as a person holding the post cannot be removed through such an informal meeting of councillors.
Last week on Thursday, Hakim went hammer and tongs against Dutta for hobnobbing with Roy - "a person who is our enemy and has a hand in killing our workers, beating up our activists and torching our party offices".
Hakim said Dutta's actions and statements were causing "big embarrassment" to the party.
He said he has placed a report regarding Dutta before the party's disciplinary committee.
"We can't tolerate somebody behaving in such a manner while being in the party. so I will definitely urge the disciplinary committee to take the strongest possible action against him. He is indispensable. He is free to leave the party," he said.
"He is a traitor, he is a Mir Jafar," said Hakim about Dutta, who had led a march of disgruntled state electricity board employees at its headquarters on Tuesday demanding a salary hike. The rallyists had ransacked the office.
But Sabyasachi responded within hours. "If by leading a march of workers, I become a Mir Zaffar, then I would choose to lead more such marches," he said.
Trinamool disciplinary committee chairman Partha Chatterjee said "if anybody sullies the image of the party, irrespective of his stature, the party would take the requisite action."
There have been speculations over Dutta's political intentions ever since Trinamool turned BJP leader Mukul Roy dropped in at his Salt Lake residence before the elections.
The incident was followed by a controversy over a social media post that apparently came from Dutta's mobile.
( With inputs from IANS )