Dr Jeeves Wijesuriya, a general practitioner trainee and also the current chair of the junior doctors' committee at the British Medical Association (BMA), rushed to the aid of those injured in the attack after hearing screams in Westminster Palace.
At the scene outside Parliament, Wijesuriya performed emergency treatment on two of the injured including the attacker - shot dead by police officers responding to the incident, the metro.Co.Uk reported.
"The police got me in to help at the scene. We gave the officer cardiac massage and spent 52 minutes trying to resuscitate the other man. We did everything we could, in terms of basic life support and starting to triage injured people at the scene," Wijesuriya said.
Fellow medic, surgeon Simon Fleming, praised his colleague on Twitter, "Chairman of the junior doctors committee doing his job as responder. Patients first. #Proud."
Wijesuriya also tweeted: "Home safe. Humbled by incredible efforts of paramedics, Met police & Helicopter emergency medical service. Thoughts with those in hospitals tonight receiving & giving care.