KOLKATA: In a major setback for the TMC amid deepening internal rebellion, senior leader Sukhendu Sekhar Roy on Monday announced his resignation as member of Rajya Sabha and also quit the party.On Monday, Rajya Sabha chairman CP Radhakrishnan accepted Roy’s resignation before declaring the seat vacant. Roy had met the chairman earlier and handed over his resignation, news agency PTI reported.A statement issued by the Rajya Sabha secretariat stated, "Shri Sukhendu Sekhar Ray, an elected Member of the Council of States (Rajya Sabha), representing the State of West Bengal, resigned his seat in the Rajya Sabha and his resignation has been accepted by the Chairman, Rajya Sabha w.e.f. 8 June, 2026."While informing about his resignation, Roy said, "I have met Rajya Sabha chairman and submitted my resignation. I have conveyed my decision to resigning from the party through WhatsApp and email to Mamata Banerjee." "I had my tenure till 2029 in the Rajya Sabha, but I have resigned in principle from the party as it would be difficult for me to continue," he added further.Roy's exit comes days after the TMC suffered one of the biggest rebellions in its history, with 58 of its 80 MLAs in the West Bengal Assembly breaking away from the party's legislature wing and securing recognition as the principal opposition bloc under expelled MLA Ritabrata Banerjee.In his resignation letter, Ray launched a sharp attack on the Trinamool Congress, attributing its crushing defeat in the recent West Bengal Assembly elections to what he described as the party's "15 years of anarchic rule" under Mamata Banerjee.He alleged that the TMC government's tenure was marked by rampant corruption, atrocities against women, and failures in key sectors such as healthcare, education, industry, law and order, and employment.Referring to the election outcome, Ray said voters had delivered a historic mandate in favour of the BJP to bring an end to the TMC's long rule in the state. He argued that public dissatisfaction with governance and corruption had led to the party's downfall.The former Rajya Sabha MP also praised the newly elected BJP government, saying it had begun implementing measures for West Bengal's development and reconstruction in line with its poll promises.Stating that he was accepting the people's verdict with humility, Ray announced that he had resigned both from the Rajya Sabha and from the primary membership of the All India Trinamool Congress.The resignation has heightened concerns within the party that the rebellion, which has already upended the TMC's position in the Assembly, could now spread to Parliament.Mamata Banerjee reached Delhi on Sunday, while party national general secretary and Lok Sabha leader Abhishek Banerjee had arrived a day earlier amid frantic efforts by the leadership to prevent further defections.According to party sources, the TMC is trying to avoid expelling dissident MPs and instead hopes to prevent rebels from gathering the two-thirds support required under anti-defection rules to split the parliamentary party. In the Lok Sabha, the TMC has 28 MPs, meaning at least 19 members would be needed to form a separate group without attracting disqualification.Reports suggest rebel MPs are considering approaching Lok Sabha Speaker Om Birla to seek recognition as a separate bloc and remove Abhishek Banerjee as the party's parliamentary leader.The crisis has triggered intense political activity in Delhi, with senior TMC leaders engaged in backchannel talks aimed at containing the damage and preventing more MPs from crossing over.Only days ago, Roy had publicly warned that the Assembly revolt could be replicated in Parliament, saying a similar reaction was possible in both the Lok Sabha and Rajya Sabha. His departure is likely to fuel speculation that more leaders may follow suit.The rebellion, directed largely against Abhishek Banerjee's growing influence within the organisation, has been informally dubbed "Operation Crown Prince" by dissident leaders.Despite the turmoil, senior TMC leaders have sought to project confidence. Party MP Sougata Roy accused the BJP of attempting to engineer defections and insisted that Mamata Banerjee would overcome the challenge.