Seven Hong Kong democracy campaigners, including former lawmakers, were sentenced on Saturday to up to 12 months in jail for their role in a protest last year against a sweeping national security law imposed by China.

The seven had pleaded guilty to charges that included organising the unauthorised assembly on July 1, 2020, when thousands of protesters took to the streets. Police, who had banned the demonstration citing coronavirus restrictions, fired tear gas and water cannon to disperse them.

The activists included...