A fire which left a man in a critical condition in hospital with serious burns is being investigated by police.
Scotland Yard said detectives from Greenwich CID were investigating the blaze at a south-east London nightclub, believed to be Studio 338.
The man, in his 20s, was taken to an east London hospital and the Metropolitan Police said he was left "fighting for his life".
Police were called to Boord Street, Greenwich, by the London Fire Brigade at 11.55am on Monday.
Fourteen men were arrested on suspicion of arson. They were taken to south London police stations and later de-arrested.
More than 12 hours after police were called, cordons were still in place at the scene and police said inquiries continued with investigators from the London Fire Brigade. The Health and Safety Executive has also been informed.
Around 100 firefighters and 15 fire engines attended the blaze at its height, which sent smoke into the sky which could be seen across the capital.
The LFB said it broke out on Tunnel Aveneue and a large part of the ground floor of the club and part of its first floor had been alight. An industrial warehouse and a scrap paper processing yard, along with 40 pallets of paper, were affected.
Some gas cylinders were also affected and a safety cordon was put in place until the cylinders were cooled.
Just before midnight on Monday, eight fire engines and around 60 firefighters and officers remained at the scene.
Station manager Andy Walton said: "Firefighters are making good progress but there is still quite a lot of smoke coming from the fire so we are still advising people to avoid the area if possible and for those living nearby to continue to keep their doors and windows closed as a precaution.
"Crews will remain at the scene throughout the night fighting the fire from outside the nightclub as the building is too structurally unsafe for our firefighters to enter. They are also dealing with deep seated pockets of fire which are still affecting the paper processing site."
Anyone with information is asked to call the police non-emergency line on 101 or Crimestoppers on 0800 555 111.