The black-and-white images shows Mr Tam being approached by a male assailant and then walking onto the road in an attempt to get away. The hooded attacker then chases Mr Tam across the street - running in front of an oncoming car, which is forced to stop - before catching him and forcing him to the ground.

He then appears to strike Mr Tam on the head at least twice with an object before grabbing his bag and running away.

Mr Tam lies prone in the middle of the street for several seconds before trying to get up. In the immediate aftermath of the assault, police called his injuries “severe” and “life threatening” .