Elected to power in 2001, Thaksin Shinawatra, a telecoms tycoon-turned-politician, draws his support from Thailand's rural poor, particularly in the country's north and northeast.
As head of the Thai Rak Thai (Thais Love Thais) party, he was the first Thai prime minister to complete a full term in office and was re-elected in a 2005 landslide victory.
Thaksin started his career in Thailand’s police force, becoming a lieutenant colonel before eventually standing down.
He started a small computer dealership in 1987, building it into the Shin Corporation, Thailand's biggest telecoms conglomerate.
Thaksin's support was greatest in the countryside, buoyed by his village welfare, cheap rural loans and job creation schemes.
But critics accused him of corruption, with his ShinCorp telecommunications profiting massively from government contracts and concessions.
Allegations of corruption, as well as accusations that he had insulted the revered monarchy, eventually led to street protests by the yellow-shirted People's Alliance for Democracy (PAD).
The protests paved the way for the military to launch a bloodless coup in September 2006, while Thaksin was out of the country.
Apart from a brief return to Thailand in 2008, Thaksin has based himself in self-imposed exile in Dubai, the United Arab Emirates, ever since.
In October 2008, Thailand's supreme court found Thaksin Shinawatra, the former prime minister, guilty of violating conflict-of-interest laws while in office, and sentenced him in absentia to two years in prison for breaking conflict-of-interest laws in a government agency's sale of land to his wife.
Thaksin, in exile in London at the time, dismissed the charges as politically motivated.
His estimated $2bn fortune has also been frozen.
Thaksin's youngest sister Yingluck Shinawatra is running in the July 3 general elections to become the first female prime minister of Thailand.
Her bid is with the Pheu Thai Party, as its party list candidate. Pheu Thai is the latest incarnation of the Thai Rak Thai (TRT) Party, which was founded by Thaksin in 1998.
Critics of Thaksin say Yingluck is his way of mainting his hold in the Thai power structure, despite being out of the country and in exile.
In an interview with Al Jazeera, Thaksin denied such "dangerous" allegations, saying that his reason for backing his sister in her run for office is because "she is the best person for the job".
Those opposed to Thaksin accused him of corruption, pointing to the number of government contracts and concessions that the Shin Corporation secured.
But those living in rural areas considered Thaksin a hero who had introduced village welfare and job creation schemes.
Thaksin aimed to capitalise on this support in April 2006, when he called for an election to be held. His opponents boycotted the vote and it was later cancelled.
While sitting as Thailand's acting prime minister following the cancelled vote, Thaksin was overthrown in September 2006 in a bloodless coup while he was outside the country.
The coup came in the wake of a lengthy street campaign by opponents, who had criticised the sale of the Thaksin family's stake in Shin Corporation for a tax-free $1.9bn to a Singapore state company.
Following the coup, the Thai Rak Thai party was dismantled amid claims that it had indulged in electoral fraud.
Thaksin and 111 senior party members were barred from politics for five years after an investigation by Thai authorities.
With further corruption investigations against him well under way, Thaksin skipped bail and fled to Britain with his wife.
In July 2008, she was found guilty by a Thai court of tax fraud and was sentenced in absentia to three years imprisonment.
Thaksin has consistently denied the charges against him as being politically motivated and has continued to sink millions of dollars into overseas investment.
In July 2007, Thaksin bought Manchester City, a football club playing in the English Premier League, for $164 million.
Though Thaksin's political allies won massive support in Thailand's first poll since the coup, he has said that he does not want to make a comeback in Thai politics.
His opponents have said that Thaksin could yet return to the country, but the verdict by the supreme court means this is unlikely.
Nevertheless, Thaksin's aides say he is ready to return to Thailand to clear his name. In November 2008, he divorced his wife, Pojaman, in what observers believe could be a strategic precursor to his return to active politics.
In December, the former prime minister, delivered a pre-recorded video address to thousands of his supporters who had gathered in a Bangkok sports stadium.
He accused the army of meddling in the country's political affairs.
"At the moment the army is interfering ... those people who interfere in the formation of a government must stop and withdraw," he said in a pre-recorded video address on Saturday.
"We are still under a military coup ... they have used the court to crack down on politicians.
"There is no other place in the world where a party has been dissolved twice," he said, referring to the banning of his political party Thai Rak Thai and its successor People Power Party (PPP).
He also urged the army to "respect the people's decision" and "behave with a sportsman's spirit and not intervene".
Pro-Thaksin supporters, called 'Red Shirts', have been mounting repeated demonstrations hoping to force Abhisit Vejjajiva, the current prime minister, from office.
On 7 April 2010, Thaksin promised the protests would mark a "historic day for Thailand".
"We will come peacefully but we need as many people as possible to show that the Thai people will not tolerate these politics any more," he said by videophone to supporters at a rally outside Government House.
Abhisit came to power in December after a court ruling removed Thaksin's allies from government.
The court decision had come after a long street campaign by anti-Thaksin protesters called 'Yellow Shirts', who claim allegiance to the Thai monarchy and fought to oust Thaksin's allies after their protests also led to the 2006 coup that toppled Thaksin.
The country remains deeply divided between Thaksin's followers among the urban and rural poor, and his foes in the traditional power circles of the palace, military and bureaucracy.