In the year since making an unprecedented, taboo-breaking speech openly calling for discussion on the role of Thailand's powerful king, human rights lawyer Arnon Nampa has spent months in jail, charged with the crime of defaming the monarchy.

He's one of 103 people from Thailand's youth-led anti-government protests now charged with insulting or threatening King Maha Vajiralongkorn or his immediate family, a crime punishable by up to 15 years' imprisonment. Hundreds more face other criminal charges.

Arnon, 36, says he has no regrets and vows the prosecutions won't crush the anti-government movement, which in recent weeks has been building again.