The crisis engulfing the TMC deepened on Monday as 20 Lok Sabha MPs, led by Chief Whip Kakoli Ghosh Dastidar, wrote to Speaker Om Birla declaring support for the BJP-led NDA, triggering a split in the party’s parliamentary unit and dealing a severe blow to Mamata Banerjee’s authority after the party’s Assembly poll debacle.

The development comes barely days after the TMC leadership suffered a setback, where 58 of its 80 MLAs defied the party high command’s decision to appoint veteran leader Sovandeb Chattopadhyay as the Leader of the Opposition, and elected expelled MLA Ritabrata Banerjee to that post.