The control of Trinamool Congress (TMC) seems to be slipping away from its founder Mamata Banerjee with a rebel faction in the party on Monday "replacing" her as the chairperson and electing senior MLA Arup Roy to the post — the latest big blow in the ongoing internal turmoil that has been rocking the outfit since losing the recently concluded West Bengal Assembly elections to the Bharatiya Janata Party (BJP).L: TMC founder and former West Bengal CM Mamata Banerjee | R: Arup Roy, picked as TMC chairperson by rebel leaders of the party (Reuters and ANI)Sources in the rebel camp claimed around 60 of the TMC's 80 MLAs attended or endorsed the session, according to a PTI news agency report. They also said nearly 70 former councillors of the Kolkata Municipal Corporation and representatives from several districts participated.Responding to the emergence of a parallel leadership structure, TMC disciplinary committee later issued show-cause notices to several senior leaders, including Firhad Hakim, Aroop Biswas, Arup Roy, Javed Khan, Rathin Ghosh, Biplab Mitra, Snehasis Chakraborty and Sabina Yasmin, alleging that they deliberately indulged in anti-party activities, news agency ANI reported.TMC crisisThe struggle to keep the party intact and herself as the commander-in-chief began for Mamata Banerjee in the beginning of this month with assembly speaker, Rathindra Nath Bose, on June 3 recognising as many as 58 rebel TMC legislators as the principal opposition party in the House. Ritabrata Banerjee and Sandipan Saha, whom the Mamata-led TMC expelled on June 1, became the leader and deputy leader of the opposition, respectively. The development took place 29 days after the Bharatiya Janata Party wrested 207 seats against the TMC’s 80.Days later, another rebel faction — of 20 MPs — emerged out of the TMC, adding to the woes of Mamata Banerjee, who by this time was abandoned by most of the elected party leaders and was left with only a few lawmakers by her side, including Mahua Moitra, Kalyan Banerjee and Derek O'Brien.Ritabrata Banerjee and Sandipan Saha were expelled on June 1, minutes after chief minister Suvendu Adhikari told reporters that they had filed a written complaint which led to the CID probe into the forgery of signatures of some TMC MLAs in a May 19 resolution that nominated Sobhandeb Chattopadhyay as the leader of the opposition (LoP).The team of MPs, led by Kakoli Ghosh and featuring several TMC heavyweights like Saayoni Ghosh, Yusuf Pathan, Rachna Banerjee etc., proposed merger with a lesser known Tripura-based party NCPI to support the BJP-led National Democratic Alliance in Parliament. If the merger goes is approved by Lok Sabha Speaker Om Birla, the NDA's strength in the Lok Sabha will rise from 294 to 314 seats, still 46 short of the two-thirds majority mark. In the Rajya Sabha, the ruling alliance could reach 155 seats, just eight short of the two-thirds threshold.