Thailand's divisive former premier Thaksin Shinawatra is expected to return to the kingdom from exile on Tuesday, threatening fresh instability on the day parliament votes for a new prime minister after three months of political deadlock.On Saturday, days after announcing a deal with the ex-party of outgoing Prime Minster Prayut Chan-o-cha -- who came to power in a coup in 2014 -- Paetongtarn said her father would return home just hours before parliament votes for a premier.