Police in Croydon had appealed to the public to help identify a man who was found collapsed in Kendra Hall Road in Croydon at around 11:39hrs on Thursday, 21 December.
A member of the public had found the man unconscious; he had apparently suffered a heart attack.
Following the appeal next of kin are now aware.
The male remains in intensive care at a central London hospital in a critical condition.
The incident is not being treated as suspicious.