Mamata Banerjee is "the most secular leader" in the country, a number of ex-AIMIM leaders said Monday as they joined the Trinamool Congress in Bengal and promised that neither the BJP nor AIMIM chief Asaduddin Owaisi would make any political gains ahead of next year's Assembly polls. "Mamata Banerjee is the most secular leader in India. She has championed the Muslim cause (and) has been criticised for it. She is the only leader in the country who was on the road to opposed NRC (national register of citizens)," Anwar Hasan Pasha, who led the 20-strong AIMIM team that switched sides at the Trinamool's headquarters in Kolkata, said.