Sam Rainsy - the charismatic leader of the Sam Rainsy Party (SRP) - is one of the most outspoken figures in Cambodian politics.
Sam Rainsy has some powerful enemies
French-educated Sam Rainsy started his working life in Paris, where he ran his own accountancy firm.
His began his political career with Prince Ranariddh's Funcinpec party, becoming a European representative for the prince in 1989.
1949: Born in Phnom Penh
1965: Left Cambodia for France
1989: Became Funcinpec's European representative
1993: Became finance minister
1994: Expelled from Funcinpec
1995: Founded the Khmer Nation Party, later renamed Sam Rainsy Party
2003: Party polls 22% support in national elections
Feb 2005: Leaves the country after losing parliamentary immunity
He returned to Cambodia in 1992, and became finance minister after Funcinpec's success in the 1993 elections.
But in 1994 he was expelled from the party following a vote of no confidence against him.
He was stripped of his seat in parliament and a year later founded his own party, the Khmer Nation Party.
Mr Rainsy has some powerful enemies. In 1997, he nearly fell victim to a grenade attack during a political rally outside the National Assembly, which killed at least 16 of his supporters.
He blamed the attack on supporters of Hun Sen - the prime minister and head of the ruling Cambodian People's Party, whom he claimed was determined to "seize absolute power by any means".
Before the 1998 elections, the Khmer Nation Party changed its name to the Sam Rainsy Party.
But the newly-named party only won 14% of the vote, corresponding to just 15 seats in government.
In the 2003 poll, the Sam Rainsy party did decidedly better, coming second behind Hun Sen's CPP, with 22% of the votes.
After an 11 month stalemate, in which none of the three main parties could agree on how to form a new coalition government, Funcinpec leader Prince Ranariddh agreed to a deal with Hun Sen.
Sam Rainsy Party MPs boycotted the new National Assembly, claiming the other two parties violated constitutional procedures in forming the new government.