Dozens of firefighters worked to tackle a fire in Ciba Apartments at the corner of Union Street and Great Guildford Street on Tuesday afternoon.
12 fire engines and 81 firefighters and officers were dispatched to the incident, which took place just a few yards away from the headquarters of the London Fire Brigade..
Part of the third floor and the fourth floor of the five-storey block of flats and offices were alight and crews reported heavy smoke logging on the fourth floor of the building.
One person left the building before the arrival of the brigade and there were no injuries.
Station manager Mark Reed said: "When crews arrived, thick smoke was drifting across the rooftops of Southwark and our control centre received multiple calls about the fire.
"Crews worked quickly to contain the fire and minimise it's spread and they will now be cutting away at the building to ensure that the fire is not smouldering in ceiling and wall voids."