The boy was detained at a bus stop on Masons Hill in Bromley until other officers arrived at the scene.
A spokesman for the Met; Police said: We’re aware of a video showing a male being detained in Masons Hill, Bromley earlier. An off duty officer bravely intervened after a robbery where a phone was stolen and threats of knives were used. He safely restrained the 14-year-old suspect until on-duty officers arrived.
