A heroic bystander foiled a protest attempt at the London Marathon by leaping off a motorbike and dragging two protesters to the ground. The mystery man, who was a London Marathon event staff member, intervened after the protesters disrupted the men's elite race by throwing red powder into the air. The protesters were arrested and remain in police custody. The incident was the latest stunt by Youth Demand, a protest group vowing to 'shut down' London this summer.