Paramedics were called to Old Broad Street in the City of London around 9.30am today.
A large number of emergency services arrived including police and the air ambulance.
Doctors treated a man but he died at the scene.
A London Ambulance Service spokesperson said: “We were called today (Weds) at 9.29am to reports of a person unwell in Old Broad Street, EC2.
“We sent resources including ambulance crews, advanced paramedic practitioners, an incident response officer and London’s air ambulance.
“We treated a man at the scene but sadly, despite our efforts he was pronounced dead.”
City of London Police has been contacted for comment.
