Thailand's junta-appointed reform council Sunday rejected a new constitution aimed at steering the country out of political turmoil, a move likely to extend the military's time in power and delay elections.
Critics had pilloried the document as divisive, anti-democratic and aimed at prolonging military rule.
But its rejection at a vote by the National Reform Council means the painstaking process of drafting a charter will now start again, potentially knocking back the timetable for elections which had been slated for mid-late 2016.
Of the 240 NRC members who voted, a majority of 135 were against the document, leaving 105 in favour.
"Those in favour were less than half of NRC members, it means this NRC meeting has voted against" the charter, NRC chairman Tienchai Kiranan said in a televised count.
The army seized power from an elected government in May last year, promising to reboot the country after years of rival street protests and political acrimony.
The junta has said a new charter -- Thailand's 20th since it abandoned absolute monarchy in 1932 -- holds the key to bridging those divides before democratic elections can be restored.
For years the kingdom has been split between pro-democracy supporters of ex-premier Thaksin Shinawatra's populist parties and a conservative, royalist elite flanked by the military and judiciary.
Shinawatra parties have won every election since 2001 and in response have been battered by two coups and the removal of three prime ministers by the courts.
- Election delay -
Opponents of the charter said it was a blatant attempt to embed the military's political power for good and would prevent genuine democracy from taking root.
They pointed to "section 260" that allows the military to replace any elected government with an appointed 22-member "crisis" panel at any time in the five years after the charter is enacted if unrest or political deadlock, as they see it, requires it.
The panel would be stacked with military top brass and other unelected officials, effectively guaranteeing the military's grip on power.
Ahead of Sunday's vote the toppled Peau Thai party labelled the charter "dictatorial" saying it would destroy democracy and plunge the kingdom into even "deeper political polarisation".
But analysts say the no vote is also politically expedient for the junta as it sets back the return of democracy.
The junta has a month to appoint a new charter drafting committee.
"They will then draft a new charter within 180 days and then it will go to a national referendum," NRC member Paiboon Nititawan told AFP.
"It will delay elections about six or seven months," he added.
The junta had slated elections for the second half of 2016 and any delay will dismay its opponents.
They accuse the military of overseeing a freefall in human rights since the coup, with dissent quickly stamped out and civilians facing trial in military courts.
Sunday's vote comes at a time of growing uncertainty about the country's future once the reign of ailing King Bhumibol Adulyadej, 87, comes to an end.
The king, who endorsed May's coup but has no official political role, is seen as a unifying figure in the bitterly divided nation.