Four fire engines and around 25 firefighters tackled a fire at a block of flats on Summerhill Way in Mitcham.
A four roomed flat on the second floor was destroyed by the fire. One person left the building before the Brigade arrived. A man was taken to hospital by London Ambulance Service.
Control Officers took the first of four calls at 2323 and mobilised crews from Mitcham, Wimbledon, Tooting and Norbury fire stations to the scene. The fire was extinguished by 0040.
The cause of the fire is under investigation.