In an unprecedented move, the sister of Thailand’s king has joined the race to be the country’s next prime minister.

According to registration papers, Princess Ubolratana Mahidol (67) will stand for a party allied to ex-prime minister Thaksin Shinawatra,.

Her decision breaks with the tradition of the Thai royal family publicly staying out of politics.

Thailand’s election is scheduled to take place on 24 March.

The election is being closely watched as the first chance for Thailand to return to democracy after five years under military rule.

Born in 1951, Princess Ubolratana Rajakanya Sirivadhana Barnavadi is the oldest child of Thailand’s late King Bhumibol Adulyadej.

The country’s current prime minister, Prayuth Chan-ocha, also announced on Friday that he would be running for prime minister in the current election.

The army chief, who seized power in a military coup in 2014, will be running as a candidate for the pro-military Palang Pracharat party.

The royal family is revered in Thailand and rarely criticised, so there are questions around whether any other candidate would want to challenge a member of the royal family.

The March vote will be the first since Mr Prayuth took power in 2014, overthrowing the democratic government and ousting ex-Prime Minister Yingluck Shinawatra, the younger sister of Thaksin Shinawatra.

Thailand’s military has a history of intervening in politics and has seized power 12 times since the end of the absolute monarchy – and the introduction of the first constitution – in 1932.

-BBC