At a rally in central Kolkata this afternoon, BJP chief Amit's Shah message and target were clear. "We are here to uproot Mamata Banerjee," he said, as thousands present at the venue cheered. Taking on the Trinamool Congress chief on her opposition to the 40 lakh people left out of the National Register of Citizens or NRC in Assam, he said Bangladeshi immigrants are Mamata Banerjee's votebank. The BJP claims Mamata Banerjee's sharp rhetoric against evicting illegal immigrants has much to do with her effort to nurture this vote bank to retain their support.