Election strategist Prashant Kishor has said opposition parties should not take the BJP lightly. "Make no mistake, BJP is a formidable force," Mr Kishor told NDTV in an interview. The election strategist's team is playing a key role for Chief Minister Mamata Banerjee's Trinamool Congress, helping it tackle the BJP challenge. "The formula we have adopted is that Trinamool should win at least 45 per cent of the vote in Bengal… A kind of advantage Trinamool has is that it has more women voters. They are coming out in large numbers to vote," Mr Kishor said. "There could be some anger in some pockets against Mamata Banerjee. But even after all this, whatever factor you take into account, Mamata Banerjee is still the strongest leader in Bengal," he said.