Two fire engines and 10 firefighters were called to a fire at a hotel on Thurloe Place in South Kensington.
A small part of a basement laundry room was damaged by the fire. Around 300 people were evacuated from the building after a smoke alarm alerted an employee.
There were no reports of any injuries and fire investigators believe oil covered robes and towels from the spa area which were placed in a tumble dryer to be the cause of the fire.
A London Fire Brigade spokesperson said: “In some cases, when towels covered in oils are put in tumble dryers and then folded and stacked, the heat from the tumble drying cannot escape.
"The high temperature builds up to a point where the towels smoulder and eventually ignite.
“If you are washing and then drying on a hot cycle, always use the cooling cycle on the tumble dryer so it cools down and allows the heat to dissipate properly, before stacking laundered items together.”
The Brigade was called at 0137 and the fire was under control by 0221. Fire crews from Chelsea and Kensington fire stations attended the scene.