Hun Sen is an enigmatic figure who has dominated Cambodian politics for two decades.
Hun Sen has been Cambodia's prime minister since 1985
The one-eyed politician, who rose quickly through the ranks of the post-Khmer Rouge government, has been Cambodia's prime minister since the mid 1980s.
A keen chess player and chain smoker, his leadership has often been controversial.
In 1997 he seized power from his co-prime minister in a bloody coup. In 2003 he was accused of fanning anti-Thai sentiments which led to rioting in the capital, Phnom Penh.
Unease about his grip on power has left him facing some influential enemies, not least in the United States Senate. A group of US Senators proposed a bill that would grant Cambodia a further $21.5m in aid if Hun Sen was not re-elected in 2003.
Khmer Rouge links
Born into a peasant family in Kompang in the summer of 1952, Hun Sen was educated by Buddhist monks in Phnom Penh.
In the late 1960s he joined the Communist Party, and for a while he was even a member of the Khmer Rouge - although he denies accusations that he was any more than an ordinary soldier.
1952: Born in Kompang
1970: Joined the Khmer Rouge
1979: Became foreign minister of the new People's Republic of Kampuchea (Cambodia)
1985: Became Prime Minister
1997: Staged coup to wrest control from Prince Ranariddh
1998: Elected back into power
During Pol Pot's tyrannical regime in the late 1970s, in which an estimated 1.7m people lost their lives, Hun Sen fled to Vietnam to join troops opposed to the Khmer Rouge.
When Vietnam installed a new government in Cambodia in 1979, he returned as minister of foreign affairs, becoming prime minister in 1985 at the age of 33.
He refused to cede power in 1993, when the Funcinpec party headed by Prince Norodom Ranariddh won the election, but acquiesced to a coalition government with the prince as first prime minister and Hun Sen himself as second prime minister.
In 1997, ignoring international criticism, Hun Sen's supporters ousted Prince Ranariddh and forced him to temporarily leave the country.
Hun Sen's Cambodian People's Party won the subsequent general election in 1998. But because he again failed to win an outright majority, he once again entered into a coalition government with Funcinpec.
In 2002, the CPP made sweeping gains in the country's first ever multi-party local elections, cementing Hun Sen's position.
In the 2003 general elections, he again gained a majority, but it took 11 months of political wrangling before he formed a coalition with the runner-up, Funcinpec. The government was finally ratified in July 2004.