Deposed Thai Prime Minister Thaksin Shinawatra has resigned as head of his Thai Rak Thai (TRT) party, a spokesman said today.
The move triggers the dissolution of its entire executive in the wake of last month's military coup.
"The changing circumstances have prompted me to preserve the future of everyone who loves the party. Therefore, I quit the party leadership," the spokesman quoted Mr Thaksin as saying in a letter.
The billionaire telecoms tycoon remains in exile in London while an army-appointed anti-corruption panel investigates his assets and business dealings.
Mr Thaksin's resignation triggered the automatic dissolution of the 119-strong executive of Thai Rak Thai (TRT), which means Thais Love Thais, although it does not mean its end as a political entity.
At least 70 TRT members of parliament quit the party yesterday in an apparent attempt to avoid any bans on politics that derive from the anti-corruption investigations that have been set up against Mr Thaksin and his former cabinet colleagues.
Former deputy prime minister and foreign minister Surakiart Sathirathai and ex-labour minister Somsak Thepsuthin led yesterday's mass resignations, the first sign of the break-up of a political party that won two landslide elections on a platform of cheap public healthcare and rural loans.
At the height of its power after the 2005 general election, TRT had three-quarters of the 500 seats in parliament.