How strangers mobilised against Hong Kong police

Tens of thousands of protesters took to Hong Kong's streets on 12 June in opposition to a bill that would allow extradition to mainland China.

The demonstrators, most of them young people, have said they had not planned their movements in advance, but began cooperating on the ground as they came under pressure to disperse from security forces.

The BBC's Rupert Wingfield-Hayes and cameraman Joe Phua were there as the clashes began and saw the spontaneous coordination in action.