The Democratic Party, founded three years before Hong Kong’s return to Chinese rule from Britain in 1997, has been the city’s flagship opposition. It used to sweep city-wide legislative elections and push Beijing on democratic reforms and upholding freedoms.

The Special General Meeting at the party’s headquarters will confirm details of the party’s “dissolution and liquidation” arrangements, according to a party statement.

Senior party members say they had been approached by Chinese officials or middlemen and warned to disband or face severe consequences, including possible arrests.

A committee has already spent around half a year making arrangements for the disbandment, including resolving legal and accounting matters, and preparing the sale of a property in the Kowloon district that now serves as its headquarters.

Disbandment requires a vote of 75% of members to pass.

The vote on ending three decades of opposition party politics in the China-run city comes a week after Hong Kong held a “patriots only” legislative council election and one day before media mogul and China critic Jimmy Lai receives a verdict in a landmark national security trial.

Under Hong Kong’s “One-Country, Two Systems” arrangement, the city is promised a high degree of autonomy and freedoms under Chinese rule. But in recent years, authorities have used the security laws to arrest scores of democrats and shutter civil society groups and liberal media outlets.

Beijing’s move in 2021 to overhaul the city’s electoral system – allowing only those vetted as “patriots” to run for public office – marginalised the party by removing it from mainstream politics.

In June, another pro-democracy group, the League of Social Democrats, said it would shut down amid “immense political pressure”.