Srettha Thavisin, until recently chief of one of Thailand's biggest real estate developers, was on Tuesday voted in as prime minister at the head of an unlikely alliance of populists and pro-military parties after weeks of post-election deadlock.

Srettha, 61, won a vote in parliament to become premier hours after the founder of his populist Pheu Thai party, Thaksin Shinawatra, made a dramatic return to Thailand after 15 years of self-exile and was taken straight to jail.

"It is an honor to be elected prime minister," Srettha told reporters after the vote. "I would like to thank all the Thai people.