TIMELINE-Unrest spreads in Thailand as coup anniversary nears

(Reuters) - Anti-government protests forced two airports to close and disrupted rail services in Thailand on Friday, piling pressure on Prime Minister Samak Sundaravej's seven-month old government.

Here is a chronology charting the political turmoil that has dogged the Southeast Asian country.

-- 2005

* September: Sondhi Limthongkul, a disgruntled former business associate, starts the People's Alliance for Democracy (PAD), a street campaign dedicated to ousting Prime Minister Thaksin Shinawatra. Sondhi argues that Thaksin's huge parliamentary majority has made him corrupt.

-- 2006

* April 2: Thaksin wins a snap election designed to silence Sondhi's increasingly biting criticism, but the victory is undermined by an opposition boycott that renders the result void. Judges annul the entire poll a few weeks later.

* September 19: Military stages coup while Thaksin is at U.N. headquarters in New York. He retreats into exile in London.

* October 1: Former army commander-in-chief Surayud Chulanont sworn in as interim prime minister.

-- 2007

* March 26: Prosecutors charge Thaksin's wife, Potjaman, her brother and secretary with tax evasion.

* May 30: Thaksin's Thai Rak Thai party is dissolved for breaking election laws. Thaksin and 110 other senior party members are banned from politics for five years.

* August 20: Voters endorse new, military-drafted constitution, the 18th in 75 years of on-off democracy.

* December 23: Pro-Thaksin People Power Party (PPP) falls just short of outright majority in a general election.

-- 2008

* Jan 8: Thaksin's wife, Potjaman, returns to Thailand after months of exile to fight corruption charges.

* Jan 28: PPP leader Samak Sundaravej elected prime minister, heading a six-party coalition.