Following are the key events in the crisis:
December 23, 2007: Samak Sundaravej leads the People Power party (PPP) to election victory.
February 6, 2008: Samak unveils a cabinet made up of members of a six-party coalition which holds nearly two-thirds of parliamentary seats.
February 28: Thaksin, who had been in self-imposed exile for 17 months, gets hero's welcome from supporters as he returns to Thailand and goes straight to court, where he is released on bail on corruption charges.
May 25: The People's Alliance for Democracy (PAD), a collection of anti-government groups, launches street protests calling for Samak to resign for seeking constitutional amendments they believe are aimed at helping Thaksin.
July 8-10: Court decisions force out of office three senior government officials - Chiya Sasomsub, the health minister, Noppadon Pattama, the foreign minister, and Yongyut Tiyapairat, the house speaker and PPP deputy leader.
July 15: A military standoff breaks out near a disputed temple on the Thai-Cambodia border, with the PAD accusing Samak of relinquishing Thai territory to help Thaksin with a business deal in the neighbouring country.
July 31: Thaksin's wife, Pojaman, is convicted of tax evasion and released on bail.
August 11: Thaksin and his wife go into exile in Britain, claiming they will not get a fair trial on the corruption charges mounting against them.
August 26: At least 35,000 PAD-led protesters raid a TV station, surround three ministries and break into Bangkok's main government compound in what they say is their "final war" against the government.
August 29: Scuffles break out between police and PAD supporters still laying siege to Government House. Protests spread, forcing the temporary closure of three airports at southern tourist hubs and a disruption to rail services.
September 2: Samak declares a state of emergency in Bangkok after overnight clashes leave one dead and dozens injured, allowing the army to move in to help restore order.
September 2: Thai election commission finds the PPP guilty of buying votes during December's general election and recommends the Supreme Court disband the party.
September 3: Thousands defy emergency law to continue occupation of Thai prime minister's office grounds.
Thai army declines to move on the demonstrators despite being given additional powers to restore public order.
Calls by 200,000-strong State Enterprises Workers' Relations Confederation for a general strike to bolster street protesters' demands fizzle out as workers go about business as usual.
Tej Bunnag, the Thai foreign minister and a former royal adviser seen as Samak's link to the royal palace, resigns, a move widely seen as jumping from a sinking ship.
September 4: Samak refuses to quit, saying he sees no reason to dissolve parliament, and vows not to bow to opponents which he calls a "freak cult".
Government approves plan for national referendum to "ask public opinion" reportedly on whether Samak should stay in office.
September 8: Samak appears in court to answer charges that he violated the constitution by hosting a televised cooking show while in office - a charge that could force him to resign if he is convicted.
September 9: Constitutional court finds Samak guilty over conflict of interest in hosting cooking show, and orders his resignation. The PPP declares it will re-nominate him.
September 11: Samak accepts his party's decision but the endorsement is opposed by protesters, the political opposition and some coalition partners.
September 12: A vote in Thailand's parliament to select a new prime minister is delayed until the following week after opposition MPs and some members of the ruling coalition stage a boycott.
Samak abandons attempt to be reinstated as prime minister, according to an aide, and decides to step down as PPP leader after the party withdraws its support for him.
September 14: Somchai Wongsawat, the acting prime minister, lifts state of emergency in Bangkok after meeting the army chief and senior security officials.
October 7: Deputy prime minister resigns after hundreds of protesters are wounded in police action and a woman is killed in a bomb blast in Bangkok.
October 21: While still outside Thailand, Thaksin is found guilty of corruption by Thai supreme court and is sentenced in absentia to two years in jail.
November 4: One person is killed and at least 60 are injured in bomb blast near a local government office in Narathiwat state.
November 8: Britain revokes visas of Thaksin and his wife.
November 13: At least 13 are hurt in a bomb attack at a street market in Bangkok, where anti-government protesters had gathered.
November 14: Thaksin divorces wife, Pojaman, in what an ally indicates could be a strategic precursor to his return to active politics.
November 20: One killed and 23 wounded in grenade attack at protesters' camp at Government House.
November 20: Thaksin ally says former prime minister set to return to Thailand's political fray to "fight back by all means ... to defend his name".
November 22: At least eight anti-government protesters are injured in an apparent grenade attack outside the Thai prime minister's office, which the demonstrators have occupied since August.
November 25: Hundreds of anti-government protesters storm Bangkok's Suvarnabhumi international airport, the sit-in protest soon begins to impact the country's lucrative tourist trade.
November 27: Protesters converge on Bangkok's second airport, Don Muang, shutting it down.
Somchai declares emergency at airports and warns protesters to leave.
November 28: Government backs down from threat to use force to remove protesters at airport, saying it will use non-violent means and negotiations.
November 29: Another grenade attack on protesters at Government House injures about 50 people.
November 30: Police warn protesters to end airport blockade but they remain defiant and refuse to leave.
December 1: Anti-government protesters begin leaving months-old camp at Government House to reinforce colleagues at airport.
December 2: Thailand's Constitutional Court orders dissolution of ruling People Power party and other coalition parties for electoral fraud, banning Somchai and other leaders from politics for five years.
The ruling, in effect, forces the government out of power.
December 3: PAD-led protesters declare victory over government and end airport siege.
The Association of South-East Asian Nations (Asean) postpones a December summit in Thailand until March, due to the political turmoil.
December 4: Deeply revered King Bhumibol Adulyadej fails to deliver his traditional birthday speech to the nation due to illness, sparking further anxiety in the population.
It is the first time he is unable to deliver the speech in more than six decades on the throne.
December 7: Members of People Power party reconstituted as Phuea Thai party (For Thais party), meet to attempt to form new government and hold on to power.