麻豆约拍

Dozens of former opposition lawmakers and pro-democracy activists have been arrested in Hong Kong accused of trying to "overthrow" the city's government.

The group were involved in an unofficial "primary" vote to select opposition candidates ahead of postponed 2020 elections.

It's the biggest mass arrest operation to take place under the controversial national security law, since it came into effect at the end of June last year.

The South China Morning Post's Bernice Chan describes what happened.

(Picture: Pro-democracy activist Lester Shum is taken away by police officers, 6th January 2021. Credit: Reuters)