Hong Kong's largest union announced it decided to disband on Tuesday citing "huge pressure" as authorities stamp out the city's democracy movement and impose political orthodoxy on the finance hub.
Founded in 1973, the Professional Teachers' Union (PTU) was the city's single largest union with some 95,000 members and was a prominent player in the democracy movement.
"After discussions, the executive committee unanimously decided to disband the union," Fung Wai-wah, PTU president, told reporters, describing the decision as "heart-wrenching".
"The social and political environment has quickly changed in recent years, we are under huge pressure. We can't find a way to resolve the crisis we are now facing," he added.
China has cracked down on its opponents since huge and often violent democracy protests convulsed the city two years ago.
A sweeping security law has criminalized much dissent while an official campaign has been launched to purge the city of those deemed unpatriotic.
The PTU was one of the more moderate voices within the democracy movement -- often shunned by more radical forces who felt it was too soft on the government.
But it still came under sustained attack by local and Chinese authorities who believe teachers played a key role in motivating Hong Kong's youth to hit the streets in huge numbers two years ago.
Last month, multiple Chinese state media outlets ran articles criticizing the union as "a malignant tumor that must be removed".
Hours later, Hong Kong's education bureau said it was severing ties with the union, saying it had become "no different from a political body".
City leader Carrie Lam later accused the union of allowing "anti-government and anti-Beijing sentiments" into classrooms and campuses.
Since Beijing imposed its national security law just over a year ago more than 30 political and professional groups have disbanded to avoid legal risks according to an AFP tally.
More than 120 opposition leaders and activists have been arrested by a new national security police unit. Some 60 have been charged, most of them denied bail.