Yangon (AFP) - Myanmar’s deposed democratic leader Aung San Suu Kyi marked her 80th birthday in junta detention on Thursday, serving a raft of sentences set to last the rest of her life.

Suu Kyi was the figurehead of Myanmar’s decade-long democratic thaw, becoming de facto leader as it opened up from military rule.

But as the generals snatched back power in a 2021 coup, she was locked up on charges ranging from corruption to breaching Covid-19 pandemic restrictions and is serving a 27-year sentence.

“It will be hard to be celebrating at the moment,” said her 47-year-old son Kim Aris from the UK.

“We’ve learned to endure when it’s been going on so long.”

He is running 80 kilometres (50 miles) over the eight days leading up to her birthday, and has collected over 80,000 well-wishing video messages for his mother.

But Suu Kyi will not see them, sequestered in Myanmar’s sprawling capital Naypyidaw from where the military directs a civil war against guerilla fighters.

Aris said he has heard from his mother only once via letter two years ago since she was imprisoned.

“We have no idea what condition she’s in,” he said.

While she remains hugely popular in the majority Buddhist country, her status as a democracy icon abroad collapsed before the military takeover after she defended the generals in their crackdown against the Rohingya Muslim minority.

Hundreds of thousands were sent fleeing to neighbouring Bangladesh under her rule, though some argued she was powerless against the lingering influence of Myanmar’s military.

Nonetheless institutions and figures that once showered Suu Kyi with awards rapidly distanced themselves, and her second round of imprisonment has received far less international attention.

- Locked away birthday -

Suu Kyi, the daughter of Myanmar independence hero Aung San, became a champion of democracy almost by accident.

After spending much of her youth abroad, she returned in 1988 to nurse her sick mother but began leading anti-military protests crushed by a crackdown.

She was locked up for 15 years, most of it in her family’s Yangon lakeside mansion where she still drew crowds for speeches over the boundary wall.

The military offered freedom if she went into exile but her poised refusal thrust her into the spotlight and won her the 1991 Nobel Peace Prize.

This time, she disappeared from the public eye on the eve of the coup.

Aris said he fears she is suffering from untreated medical problems with her heart, bones and gums.

Myanmar’s junta offers only intermittent updates on her status and the conditions of her incarceration.

“She is in good health,” junta spokesman Zaw Min Tun told reporters in March, adding that she was provided with routine medical check-ups but was not unwell.

Suu Kyi was freed from her first confinement in 2010 and led her National League for Democracy party to electoral victory in 2015, never formally in charge as army-drafted rules kept her from the presidency.

The military has promised new elections at the end of this year, but they are set to be boycotted by many groups comprised of former followers of Suu Kyi’s non-violent vision who have now taken up arms.

If the octogenarian were released, Aris predicts she would likely step back from a “frontline position” in Myanmar politics.