BANGKOK, Sept 28 (Reuters): Thailand's Constitutional Court will rule ​on Monday on a challenge to the legality of February's general election, a decision that ‌could put part or all of the result in doubt.

The case stems from a petition filed by the ombudsman that argued that barcodes and QR (quick response) codes printed on ballot papers could be used to identify which candidate and party a voter chose, ​undermining ballot secrecy.

Nearly 38 million Thais voted in the February 8 election, which was won decisively by ​Prime Minister Anutin Charnvirakul's Bhumjaithai Party, allowing him to form a coalition government controlling more than ⁠290 of the 500 seats in parliament.

The election commission says the codes were included on ballots for security ​purposes and that identifying a voter would require access to ballot stubs stored separately.

The Constitutional Court has been ​at the heart of two decades of on-off political turmoil in Thailand, delivering verdicts that dissolved major parties, voided two general elections and brought down multiple governments and prime ministers.

Analysts say the court is likely to rule that the ballots were lawful. ​However, if it finds secrecy was breached, it could annul part or all of the election result.

"Dismissal of ​the petition is the most likely outcome," said Prinya Thaewanarumitkul, a law lecturer at Thammasat University, adding a nationwide election ‌rerun was ⁠unlikely.

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