Police were called to Skerne Road in Kington at around half past midnight today (Wednesday, October 11).
London Ambulance Service and London Fire Brigade also attended the scene.
A man in his 40s was taken to hospital after suffering burns and his condition has been described by police as “life-threatening”.
His next of kin are aware.
The man’s issues are thought to be self-inflicted and the incident is not thought by police to be suspicious.
A spokesperson for the Metropolitan Police said: “Police were called at 00:32hrs on Wednesday, 11 October to concerns for the welfare of a man in Skerne Road, Kingston.
“Officers attended along with the London Ambulance Service and the London Fire Brigade.
“A man aged in his 40s was taken to hospital in a life-threatening condition after suffering burns.
“His next of kin have been informed.
“His injuries are thought to have been self-inflicted and the incident is not being treated as suspicious.”