NEW DELHI: Trinamool Congress supremo Mamata Banerjee on Tuesday said that leaders who defected from the party will not be allowed to return.Addressing a rally on Martyrs’ Day in Kolkata, Mamata said she has “many people” to fill the places of leaders who jumped ship after the TMC suffered a huge setback in the Assembly elections.“I challenge them to join the BJP. I have no problem with that; in fact, I will be very happy. I have many people to fill their place,” Mamata said.During her address, Mamata also advised opposition parties to unite under INDIA bloc to fight against BJP.“I want everyone to unite under the INDIA alliance in West Bengal to fight the BJP. I have no ego,” Mamata said.The remarks came as TMC observed its 21st July Martyrs’ Day at Birla Planetarium in Kolkata to commemorate the 13 Youth Congress workers who were killed in police firing during a protest under the Left Front regime in 1993. TMC is facing its biggest organisational crisis since its formation in 1998. Several senior leaders and MLAs have joined a rival faction led by Ritabrata Banerjee, with many attributing their exit to Abhishek Banerjee‘s growing influence within the party.The rebellion has also reached Parliament, where several Lok Sabha MPs have broken away from the Mamata Banerjee-led camp. With rival factions now operating parallel organisational structures, the leadership tussle has emerged as the defining challenge facing the party.