A London Ambulance Service spokesman said:
"We were called at 8.39am today to reports of a patient taken unwell at London Bridge station.
"We sent two ambulance crews, a single responder in a car, our hazardous area response team and a duty manager.
"Our staff have assessed four patients at the scene who were taken unwell. Three of the patients have been taken to hospital."
More top news
Detectives appealing for witnesses to a fatal accident have a released a picture of the 29-year-old victim.
Australian paramedics are being recruited to fill vacancies at the London Ambulance Service.
Brent Council is offering to cut business rates for firms that pay the London Living Wage.