Mamata Banerjee is on the cusp of a remarkable political victory, if the latest polling is to be believed. This most resilient of politicians, the leader of the West Bengal's Trinamool Congress (TMC) party, could be about to overturn the communist stronghold in one of India's most populous states. In 2006, the TMC won 10% of the seats in a local assembly election, while the left-wing coalition won nearly 80% of the seats.