KOLKATA: Voters streamed into polling stations in India's West Bengal state Monday in a local election that could see a populist maverick unseat the world longest-serving, democratically elected communist government and emerge as a key power broker. After 34 years of communist rule, federal Railway Minister Mamata Banerjee, a firebrand orator known as “Didi” or “elder sister”, looks set to overthrow the communists blamed for leaving West Bengal and its capital Kolkata in a time-warp of Soviet era state control. “I promise to turn north Bengal into Switzerland” she told supporters with characteristic populist rhetoric at the weekend, referring to a plan to transform the area's railway network. Monday's election is centered on the remote northern part of the state. Banerjee's Trinamool Party is allied to India's ruling Congress party and her victory would give the national coalition a moral boost at a time when it has been battered by high food inflation and graft scandals. The 56-year-old's victory would also seal her position as one of India's most powerful regional politicians with the ability to influence Singh's government, which is dependent on her party's 19 seats in the 545-member national parliament. Banerjee would join a group of often fickle state chiefs – including controversial “untouchables” leader Mayawati in Uttar Pradesh – that often demand a myriad of concessions like extra infrastructure and social spending as a condition for support. While her victory would strengthen Prime Minister Manmohan Singh's coalition, it would also make it more vulnerable to pressure from his populist partner. “Her attentions will be focused on West Bengal, as it is in a state of economic decline,” said Ramachandra Guha, a fellow at the Indian Institute of Management in Kolkata. “But she'll certainly have an eye on the centre, and she'll want to make sure she can still extract concessions for her state.” Results for the month-long staggered election will be known on May 13. Singh's ability to revive stalled economic reforms even after victory is seen as limited because the coalition remains pre-occupied with fighting off an opposition onslaught on the graft charges.