An air ambulance landed in Stevenage early yesterday evening after a person went into cardiac arrest.
A 999 call was made at 5.45pm to report a person suffering a cardiac arrest in Doncaster Close in Stevenage.
Two ambulances and a rapid response vehicle attended the scene and the Essex and Herts Air Ambulance was also scrambled.
One person was taken to Stevenage's Lister Hospital in a serious condition.