The opposition won Thailand's general election by a landslide on Sunday, exit polls showed, paving the way for Yingluck Shinawatra to become the country's first female prime minister in a victory for a red-shirted political movement. Television showed Yingluck, younger sister of former prime minister Thaksin Shinawatra, swarmed by flashing cameras and journalists after exit polls showed her Puea Thai (For Thais) party winning a clear majority of the 500 seats in parliament. "Let's wait for the official results. I will tell you how I feel tonight," she told cheering supporters. An exit poll by Bangkok's Suan Dusit University, considered the most historically reliable, showed Puea Thai winning 313 seats with Prime Minister Abhisit Vejjajiva's Democrat Party taking just 152. Bangkok's Assumption University (ABAC) put the number of seats won by the opposition at 299. The red shirts have rallied around Yingluck and accuse Abhisit of colluding with the army with impunity -- grievances that have simmered since a 2006 military coup overthrew her brother. Thaksin, a former telecommunications tycoon, scored landslide election wins in 2001 and 2005 by appealing to the poor with populist policies, from cheap credit to universal healthcare. Yingluck hopes to tap his supporters. Abhisit, 46, an urbane economist born in Britain and educated at Oxford, has warned of instability ahead if Yingluck wins. He blames the red shirts for last year's violence and casts Thaksin as an authoritarian crony capitalist. His backers -- the royalist establishment and urban middle class -- want Thaksin to serve a two-year prison term for conflict of interest offences. They say Yingluck is a proxy for her brother and would clear the way for Thaksin's return. Abhisit had hoped to win a mandate from the people after coming to power in a controversial 2008 parliamentary vote when a pro-Thaksin ruling party was dissolved by the courts. His Democrats have not won an election in nearly 20 years. Throughout the six-week campaign, the two sides have presented similar populist campaigns of subsidies for the poor, improved healthcare benefits and infrastructure investment including high-speed rail systems across the country. The election is Thailand's 26th since it became a democracy in 1932, ending seven centuries of absolute monarchy. It has since been governed by 17 constitutions and has experienced 18 military coups, either actual or attempted. Recent opinion polls had suggested Puea Thai would win at least 240 seats, a threshold that is no guarantee it could govern. Most had doubted it either side would secure an outright majority, predicting back-room talks with smaller parties would prove crucial for forming a coalition. Investors are watching. Thailand, Southeast Asia's second-biggest economy and a base for automakers including General Motors Co, has struggled to execute long-term planning -- from major infrastructure to much-needed economic reforms. The vote is also a test for Thailand's courts, which have handed down rulings that have removed two prime ministers, disbanded six parties, jailed three election commissioners and banned more than 250 politicians since the 2006 coup. Analysts and legal experts say those precedents suggest the courts could ultimately dictate who holds political power in the months after the election. According to some reports, the Puea Thai camp had been in talks with the generals to find some way of working together should it emerge victorious. Puea Thai would be allowed to govern and the military top brass would remain in place, with early reshuffles limited to middle ranks.