Facing a major rebellion, TMC chief Mamata Banerjee has carried out a sweeping organisational overhaul, banking on loyalists and senior leaders. Abhishek Banerjee retains a key role, while Derek O'Brien and Dola Sen step in as joint secretaries and Chandrima Bhattacharya takes charge as state president. The rejig comes even as the party moves to challenge the recognition of rebel leader Ritabrata Banerjee as Leader of the Opposition-signalling an intensifying internal battle.