Ten fire engines and around 70 firefighters were called to a fire at a health club and spa on Creek Road in Deptford.
A storage room on the first floor of a 12-storey building, containing the club and spa with flats above, was completely destroyed by fire. There were no reports of any injuries.
A road closure was in place on Creek Road by the junction of Deptford Church Street, which caused significant traffic delays. People were asked to avoid the area where possible.
The Brigade was called at 0606 and the fire was under control by 0829. Crews from Deptford, Greenwich, New Cross, Lea Green and surrounding fire stations were at the scene.
The cause of the fire is under investigation.