Four fire engines and around 25 firefighters were called to a fire at a derelict pub on St James' Road in Croydon.
Part of the ground floor in the three storey property was destroyed by fire. Five construction workers left the premises before the Brigade arrived. There were no reports of any injuries.
The Brigade's 999 Control Officers received 23 calls alerting them to the fire.
The Brigade was called at 1344 and the incident was under control by 1438. Fire crews from Croydon and Norbury fire stations were in attendance.
The cause of the fire is under investigation.