A London Ambulance Service spokeswoman added: “We were called at 8.54pm to reports of a person on the tracks at Green Park station.
“We sent multiple resources including an ambulance crew, a member of our Hazardous Area Response Team and a doctor from London’s Air Ambulance.
"The first of our medics arrived on the scene in under three minutes.
“We took one patient, a man, to hospital.”
The evacuation sparked panic among many Londoners travelling in central London, with some fearing a security incident could be unfolding.
Matt Lee tweeted saying: "Several fire engines, police cars & ambulances at green park station with air ambulance landing in the park... incredibly worrying situation."
While Felicity Lowde said: "A blizzard of sirens, fire engines & helicopters going through Mayfair. What now? Everyone evacuated from Green Park station."
Tess Hulme said: "So much scary stuff happening at Green Park. All emergency services plus air ambulance and station closed! Feels pretty mega."
And Claire Bell posted: "Air ambulance helicopters, numerous police and ambulances. What the hell is happening at Green Park? So scared right now. #greenpark."