Four fire engines and around 25 firefighters tackled a fire at a mixed used commercial building in Floral Street, Covent Garden.
Part of a boiler on the second floor and a void between the first and second floors were damaged by fire, as well as part of a first floor ceiling. There were no reports of any injuries.
The fire was discovered by a member of staff who noticed a smell of burning and saw smoke coming from toilets on the ground floor of the property.
The Brigade was called at 1320 and the fire was under control by 1521. Crews from Soho, Shoreditch, Dowgate and Shadwell Fire Stations were at the scene.
The Brigade's Fire Investigators believe the fire was accidental and caused by the ignition of timber flooring and joists caused by prolonged, radiated heat from a commercial boiler.