Police arrested a woman in central London after four men were found with stab wounds in the shopping and entertainment district

The London Ambulance Service said an ambulance crew, a paramedic in a fast response car and an incident response officer had rushed to the scene and treated the four men before transporting them to a major trauma centre by road.

However, the ambulance service also dispatched London’s air ambulance. Video posted on social media shows a red helicopter making a dramatic landing in the middle of a crowded Trafalgur Square.