Paul Benson, 67, from Barnet, collapsed in the pedestrian tunnel at the central London station while on his way to catch the Elizabeth Line with his wife, Lorraine.
An off-duty nurse, doctor, and pharmacist were nearby and immediately started chest compressions.
They used the station’s defibrillator to restart his heart before the ambulance clinicians arrived.
Paul was then taken by London Ambulance Service paramedics to the nearest Heart Attack Centre at St Bartholomew’s Hospital, where he had bypass surgery.
He is now making a good recovery.
Paul said: “It’s important that Londoners aren’t frightened to stop and help.
“It’s very easy to walk past but those who step in can save lives.
“They can’t make it any worse but they can certainly make it better.
“Thanks to their help I’ve been able to carry on with my life.”
Paul was reunited with the paramedics who saved his life at London Lifesaver training for London Assembly Members at the station earlier this week.
He added: “I was in very good hands and my good Samaritans kept me alive until the paramedics arrived.
“Without a defibrillator, I wouldn’t be here.”
Paramedic Jackson Day, one of the ambulance crews who treated Paul on scene, said: “It was great to meet Paul and see such a positive outcome for him.
“I’ve worked at London Ambulance Service for nearly seven years and this was my first time meeting someone I’ve treated who suffered a cardiac arrest.
“It was a really special moment.”
Paul is now backing the London Ambulance Charity’s Heart Starters campaign, which will work with local communities to fund additional defibrillators for the most deprived areas of the capital.
Analysis by the London Ambulance Service has revealed that dozens of neighbourhoods are ‘defibrillator deserts’ – where there is little or no access to a life-saving device.
The data has revealed large discrepancies between communities in outcomes for cardiac arrest and the availability of life-saving devices.
Mark Faulkner, Consultant Paramedic at London Ambulance Service, said: “Paul is very lucky to have survived thanks to the swift actions of bystanders.
“Sadly we don’t know who they are but we are immensely thankful for their efforts.
“Anyone can learn to do chest compressions and you do not need any specific training to use a defibrillator.
“It is these skills which saved Paul’s life.”
Chair of the London Assembly Health Committee, Krupesh Hirani AM, said: “The London Assembly Health Committee visit to Liverpool Street Station showed in graphic reality how important anyone can be in those first few minutes after a cardiac arrest.
“Saving a life sounds like a big deal – but it’s surprisingly straightforward.
“The Committee recognises the necessity of improving out of hospital cardiac arrest survival by equipping Londoners with the skills, knowledge, and confidence to act in the vital few minutes before an ambulance arrives.
“Meeting Paul, who owes his life to the passing public and London Ambulance Service crews, was a very humbling experience.
“The fine work of the LAS to raise awareness of how imperative CPR skills and defibrillator use are, is to be congratulated.”
Naomi Smith, Head of Customer Operations at Transport for London, said: “We are absolutely delighted to be working in partnership with the Mayor and our colleagues at London Ambulance Service to support this vital life-saving initiative.
“We know every second counts when saving a life, so we are pleased that as well as having first-aid trained staff at stations, our customers will have quick access to a defibrillator across the Tube and Overground.”
